True damage does not increase from % increase masteries or Abyssal

The title says it all basically, I tested this with the assassin and double edged sword mastery. I'm sure there is a reason that it doesn't benefit from increased damage masteries, however, on mages like Ahri it makes the initial proc of her Q do more damage than the rue damage return in some circumstances. Considering the return is often harder to hit, I think it should be doing more damage than the initial, like how ekko or talon has increased damage on the return of their projectile abilities.

I tested the true damage experiment on Reksai and Ahri with the only extra damage coming form the % damage increase masteries assassin and double edged blade. The true damage on Ahri Q is 40 lvl 1. With the 7% extra damage masteries the damage should have come out to be 42.8, or rounded to 43. Instead the damage came out as 40. For reksai I did the same thing. The true damage on her E read out to be 93 true damage on the tooltip, but only did 92 damage (probably for rounding reasons) in practice.

This probably is the case for all true damage in the game. I would just like to know if this is intended or not, mostly for personal reasons considering with the new abyssal you can do more damage with the initial cast from Ahri Q than with the true damage return in certain situations because of this. ( I know abyssal only increases the magic portion, I'm just saying that the magic portion of ahri q can reach 17.5% while her true damage portion doesn't get any % increase.)

EDIT : I was also using the sorcery mastery for 2% extra ability damage