I posted this over in Mola's thread as well, but I'll put it here since it will probably get more eyes/discussion. Short of it is, I emailed Idemitsu a while ago for clarification on all the things we've discussed about their H+ over the last year or so. This is their response
(Bold text done by me):
'Hello, Shawn
Thank you for reaching out to Idemitsu Lubricants America Corporation.
Your concern is important for us, so we requested our technical department to provide additional information.
The DW-1 fluid requires specific properties (for example, viscosity, viscosity retention, low-temperature viscosity, etc.) and dynamic and static friction beside standard transmission oil properties.
Taking into consideration these aspects, we would like to share with you a comparison between DW-1 and Idemitsu ATF Type H Plus:
As you can observe in the chart above, Idemitsu ATF Type H Plus meets all the key performance properties for DW-1.
Also, the static and dynamic friction performances for Idemitsu ATF Type H Plus are almost identical to that of DW-1 fluid. Each transmission fluid developed by Idemitsu undergoes strict quality testing to meet the exact frictional requirements as prescribed by the automaker.
In addition to the above, we would like to reemphasize that Idemitsu ATF Type H Plus provides several other benefits that meet and exceed the average requirements of ‘standard market' multi-vehicle transmission fluids, such as:
§ Enhanced fuel economy and superior low-temperature flow properties
§ Smoother shifting and outstanding anti-shudder performance
§ Excellent resistance to oxidation and thermal breakdown of oil
§ Superior cleanliness
§ Advanced anti-wear performance
§ Excellent seal compatibility
We understand there has been some open and passionate discussions related to the elemental analysis for DW-1, Idemitsu ATF Type H Plus and some market general multi-vehicle transmission fluids. We truly appreciate open discourse and productive feedback when it comes to the quality and performance of our products—it's the one thing we take most seriously and are proudly confident about.
Once more, we would like to reaffirm that the Idemitsu ATF Type H Plus uses a different additive package than DW-1—however, this has no bearing or impact on the formulation's ability to meet the prescribed performance properties for this particular transmission.
We hope the shared information will help clarify any doubts. Should you have any further questions, feel free to reach me via e-mail.
Best regards,
Thomas Khondaker
Product Manager, Aftermarket Oil
(Contact Details Omitted)