Here a test setup: http://imgur.com/a/gJm8O
Bottom line, superior capacity runes on
T4 ring: 2079650 LP
T5 ring: 4457915 LP

Latest version 1.3.1-7 from
http://minecraft.curseforge.com/mc-mods/224791-blood-magic/files

T4 ring is 7 runes on the side, not 9. You're counting runes that are not used in the calculation in T4, but are in T5, and that results in difference - T4 version has 56 working runes, T5 64.

...I've known this mod how long and forgot that? Derp!

Did you even look at the screenshots? I left 2 runes out on each end. Both rings have same amount of capacity runes.

Oh wait, i see what you mean. http://ftbwiki.org/images/3/31/Blood_Magic_Altar_Tier_4.png

Did you even read the comment? T4 doesn't use 9 runes per side, it uses 7. So 8 of your runes aren't counting in the T4 altar. 1.1^8 = 2.1436. 4457915/2079650 = 2.1436.

Yeah i did, also repeated the test twice to be sure.

Did you wait long enough for the T4 ring one? The numbers for the T5 are correct.