It's because no one really care of that low damage difference when they boost boss as they want.

There is prob many other littles bugs like that, that's why they boost the HP of boss.

Maybe easier to have more HP on boss than re do all armor of boss with possible problem on arpen calculation on server side or whatever, i don't know **** on programming.

If itwas a 5% buff, yeah would be huge, but, 315 armor .. ^^.