@46.5k added 2nd qt to this OCI

I can do a UOA with this last run of dollar general's "American XT" 10w-30. I still have 12qts of that left that I'll be using as "add-oil" There will likely be 2 more Oci's done during cold(er) weather. I have one more fram left that I'll use this next change and then run the few ecore stp's that I bought by accident. Those will be for warmer weather, then back to 10w-40.
Only difference noted with 10w-30 vs 10w-40 is that I had to turn down the idle about 25rpm as it would run-on when I shut the car off. The thicker oil must have had a slight braking action.

Since you just topped-off, I'd run the car until you are down a quart (another 1k-ish), and THEN do a UOA and change. Brand-new oil will skew the results without some miles on it....

Of course, with an engine that needs regular top-off, the oil will almost always look 'strong', as there is regular replenishment.

only at 3k on this oci thus far so I was going to go at least another k (2 weeks).
About every K, I need to add 1 qt with 30. Using 40, I get about 1-2 hundred more miles before adding. No matter how I do it, it'll use 7 qts to go 4k. The only difference is how low sump is at change time.
Since MS5k is a different formula oil than most, should I use the same stuff for adding, or whatever I get cheap as usual? i hate to waste good stuff for just top-offs.

Just get some Shell or Exxon Super flo conventional for top off`s.

I'd definetly just stick with the cheap stuff for top-offs.

Don't spend good money on oil that won't be in there very long, at all.

If I follow through with 4k miles, it'll be around 12/10 or so. Just a hair over 2 months. I hope to be able to get at least 3 months per change, so I may do an extra week.

Truthfully, with regular top-off, you can go further than 4k, so going a full 3 months, like you want, isn't a big deal.

'Back in the day' I think Ford called for OC's every 6k with 10W-30 or 10W-40.

Ironically, the owners manual for this car recommends oil change at 7500 miles and filter every other change using SE grade oils. Also says 10w-30 good for up to 90 deg F with 10w-40 for above that. 5w-30 not recommended for extended driving at freeway speeds or for use above 32 deg F.
My target is 5k to 3 months while minimizing consumption. Current fill would take at least another qt to reach 5k, making it 3 qts added.
Now @ 46.67k or 3.17k on oil+filter

I wouldn't want to push it with a DD you rely on, BUT, with the amount of top-off you add, 7500-mile all-highway OCI's aren't out of the question here.

If you'd be comfortable with it, you could push to 4-month 6-7k OCI's....

I think you're right.
All of that make-up oil is renewing the add pack as you go.
Ford did back off on its oil change interval recs later on.
The OM of our '97 Aerostar recommended 5K changes on what was then SJ oil, IIRC.
Anyway, SS1970, you're doing great with that old Granada.
I wish you continued good luck.

@46.75k, 3.25k on oil
If I change next weekend, I'll be around 4.2k this oci. Next will be MS5k for 5k and maybe I'll keep inching it higher depending on consumption. NOACK is much higher on MS5k than AXT I'm currently on. I won't add any of my old formula STP that I use for ZDDP just to see how this newer formula runs. There should be enough built up on cam to let it ride awhile. I'd be a bit leery of beyond 5-6k as most filters cop out around there. I've got one more OCOD from '88 to use and 4 STP ecores to use up.
I'll be switching to ST as my add-oil when the AXT is gone as it's 50% cheaper to just buy large jugs of that an refill my qt bottles. Must use qts as pouring a large jug is impossible on this engine without removing the hood.

Did you add some of this old STP to the current fill of oil?

It will be interesting to see if the 10W-30 M5K, with no additives, will be consumed faster due to lower viscosity.

@46.83k
Nope. I figured there was still a qt or so containing some still in the engine. I usually add about a half bottle (7 oz) every other change. I'd bought 2 cases of it on closeout for $1 a bottle. It was the cheapest way to add some. This inline 6 engine shouldn't really need overkill on zddp often, probably only between 800-1000 ppm should be fine. My big blocks I try to keep 1000-1200ppm.
The only different item in this oci is about 4 oz of XHD 30w that was leftover from an oci on the forklift at work. Waste not, want not.
I'm somewhat curious about this new LTi formula and how it'll perform as a zddp replacement. The only thing that'll skew the results is the fact that my add-oil will be something different, unless I buy some more.

Agree with all you've said....I'm curious about this STP you have - as long as I can remember, STP has been in a blue can/bottle...you said you're 'old' STP is in a yellow bottle/can?

Can you post a pic?

Nope. It's in a blue bottle with a large yellow box on the label. These were the last ones before they changed the formula, making it almost useless. I've only used the stuff as engine assembly/ break-in lube and for a zddp additive. Zddp plus is better, but much more expensive.
One thing I've noted about using STP as a zddp additive is that it builds up in the engine, resulting in rediculously high numbers if used every oci. Check out the UOA on a 1978 LTD that I posted awhile back. That car had a whole bottle of STP for each of the last 6 oci's that I know of. Too much of the stuff can't be good either.