[GAMEPLAY]Mejai's Soulstealer & Rabadon's Deathcap

I noticed just recently that mejai's and rabadon's do not appear to be interacting correctly together. I can have the same end game build but end up with different amounts of ap depending on the build order and if i lose stacks on mejai's or not. Rabadon's does not seem to give the 35% extra ap to the stacks if the stacks are acquired after purchasing rabadon's. One game i had 1011 ap, the next 965. I had the same exact end build, but the difference in ap was significant. is this something that can be looked in to? i did not think to get screenshots but will post them when i get them.

https://drive.google.com/file/d/0BzXeEE4kQ3wRc1FQR2dGaHlnSjQ/view?usp=sharing

https://drive.google.com/file/d/0BzXeEE4kQ3wRWDdyd1psMHhYMGM/view?usp=sharing