sounds like they are already streaching

Basically they gave you the 40% raise, but 8% of which will be one time. From my experience in negotions, it sounds like they are already reaching. If I were you, I wouldn't risk the good will for an extra few re-current %. If they are pissed off, they can always take it away from your next raise.

What's your base range btw? If it is only 50k, then 40% doesn't sound much of a raise, for example.