Kha'zix and the 10 less movespeed

Been onetricking Kha lately, and I have noticed that when I buy mobi boots, he gets 10 less movespeed than he should, meanning that out of comboat, he only gets 105. I have yet to try doing this without smite, but it appears that at any time I get the mobi boots, I get +105 movespeed out of combat instead of +115. Works any time before or after finishing your jungle item, enchantment, or any other assortment of items.

Also during testing I found that buying a Serrated dirk or any item after it, you get only +16 movespeed out of combat, but ONLY if you have mobi boots. It does not matter which you buy first. Additionally, purchasing a poachers dirk on top of the serrated dirk and mobi boots gives you only +12. This led me on to upgrade my serrated dirk to a youmuus ghostblade and purchase a new serrated dirk, which added only +10 out of combat movespeed, half of what it was intended to do.

So with Mobi boots, it looks like all out of combat movespeed items receive less and less out of combat movespeed. I didn't test any % movespeed items, but those may be interesting to look into.

I also got rid of the mobi boots and looked at just boots of speed with all of the aforementioned items, and you get +81 movespeed out of combat, but the correct +25 when in combat.

At this point, the minions in the custom game ended the game and I couldn't do any more testing on the matter.