dparm makes a good point. You see a lot of advertising with bulbs. 30% brighter, 50% brighter, 80% brighter, etc. Legally, an HB4 bulb for instance cannot put out more than 1150 lumens (1000 +/- 15%). Period. So you know the claim of "80% brighter" must be something other than "80% more lumens", because the bulb can't have 80% more lumens and be legal.
Each bulb type (let's stay with HB4 as an example) specifies where the filament is placed in the bulb, spatially, and there are allowable ranges for that spatial placement to allow for manufacturing tolerances, etc. There are a few ways to get "more light" out of a lamp housing, especially a multi-faceted reflector housing, without actually putting "more light" in it. You can move the filament in the bulb to achieve a different optical pattern on the road. This is largely where the "80% more light" claim comes from. At somewhere in that beam pattern, there probably is 80% more light with a slightly repositioned filament than with a "standard" one. Another way is to manufacture the bulb with a smaller and tighter filament. As dparm said, create something closer to a "point source". This also changes the beam pattern in a multi-faceted reflector housing (usually for the better).