[2022] Expertise +3 on Dark Winter less than Vector 9mm? Damage changing

I have a god rolled Dark Winter (so that's 15% SMG damage)
Base Damage = 40.4k
+ 3% Expertise
Total Damage = 69.9k

I also have the Vector SBR .45 ACP which the Dark Winter is based on, again it is god rolled (15% SMG damage)
Base Damage = 40.4k
NO EXPERTISE
Total Damage = 68.7k

Now to the Tactical Vector SBR 9mm
SMG damage is 10% not 15% so it's not even maxed out yet.
Base Damage = 42.3K
NO EXPERTISE
Total Damage = 69.8k

How is a smaller caliber of the same manufacturer/model type, doing more damage with less SMG damage and NO expertise?

Now get this, i jumped in to help an agent which was on Heroic, now when i come back to my own instance of the game, the Dark Winter is now doing LESS total damage!
It is now 59.0K total damage. What is going on?


EDIT: Ok, now it's 71.2K Damage. So i don't know. Does it change when you go from Normal to Heroic, then sometimes lags behind to revert when you go back to playing on Normal?