Bid Cap Help

I’m running a campaign with a $10 bid cap, and for the first time I’m getting purchases in the $3 to $5 range. The issue is that it is not spending the full budget and seems to stall out at around 7 purchases.

Would you try raising the bid cap to get more spend and volume, or leave it alone since the CPA is coming in well below target?

And if you would raise it, how aggressively would you test it?