After thinking about it a little, it might not be a bug but got something to do with the scaleing, but if thats the case it seems a little weak for a 6M+ healing when you actually skill(See what I did there?) for it. I mean graft can easily go for 220 and it only costs 3.
It doesn´t need a big buff either, but simply doing skill*2+Bonus should be ok.
(SKI * 200% + 25 Flat Heal)
with 50 Ski, 1 Apt
with 50 Ski, 60 Apt (tested to see if it's aptitude's bonuses being ignored, nope.)
Ain't 200% = 2x, anyway? In math, Meditate seems to be working like ((50 (Scaled SKI) + 25 (Flat Heal) x 200 (Multiplier)) / 100 (Percentage))
The only bug I see is the rounding error, which has been corrected. If you feel it's too weak feel free to discuss it in Balance Fu.