"I always sucked at algebra... But I get an equivalent HP of 249.5 Can someone check me on this ?"

I don't suck at Algebra and I got the same HP number you got.

Stock lbs/hp ratio is 14.79
your lbs/hp ratio is 12.74

3180/x=12.74
x=249.6

Shedding 440 lbs got you 34.6 HP!