boss damage not working on v1s?

I can vouch that v1 and v2 summons doesn't count as real bosses. That bird summon certainly did, and it has 60% PDR, I pulled off easy cap damage on the bird with my DS, but I only get around half-3/4 of that damage max on v1 and v2 summons (v1 has 50%, v2 has 60%). Since Empress has a "physical" resistance, it looks like boss % is working fine. With all bonuses combined I only have 100% boss damage, adding in demon impact and looks correct when I only deal half that on v1.

Heck, I even did more damage on CHT than these summons -_-.