Owning 2 or 3 variants of a mech should at least provide xp boosts to each variant of the mech

I was inspired by this post below, thinking that this could be a solution to the problem with getting 3 mechs from packs from the residual effects of the original 3-to-master system. Ultimately it would be better to have premium time back, but my post's solution is more like a compromise:

https://www.reddit.com/r/OutreachHPG/comments/6f09cq/dear_pgi_fix_your_mech_packs/

Since mech packs (except for hero packs) are all still sold in at least threes, one of the main reasons for purchase was to master the mechs due to needing three different variants to do so.

Now that only one mech is required, some players might not necessarily want to use the other one or two variants compared to a particular one, and neither do they help with the grind for a particular mech.

The mastery bundles are still being sold (although now under just "bundle" in-game, gift shop still has "mastery"), showing that one of the reasons to buy was "you purchased them to master them"; but removing that reason just leaves the customer with "less value", albeit not in item value.

In addition, with the removal of premium time from the regular packs, the grind is increased with the pack value further placed on the three mechs. But once again, since the "mastery value" is lost on the three mechs, it's now more for players who want to play with multiple variants or get them prior to MC/CB release dates, while those who just want to save on mech mastery and only want to use a single or two variants are now more left out.

However, if a permanent 15% xp bonus for each owned variant of the chassis was earned for owning an extra variant of the mech, up to 30% from owning three, that could mitigate the premium time issue, since for those specific mechs, it wouldn't be as much more difficult to grind them out (excluding cbill cost). In addition, it would also make more sense for the 3-mech style of pack and make the "mastery bundles" fulfill its intent on getting (a) mech(s) to maximum potential quicker. It would also add "value" in the sense that having three would be something that somebody with only one variant of the mech doesn't have.