I only use one very easy drill right at the end to adjust by 1%, which is how I noticed this. Obviously it's not a big deal, more curious than anything.
Trying to be strictly on 99% before games? It doesn't matter that much, you can easily spend 4-5% extra. There's no difference between, let's say, 94% and 99%.
Also, try out ITP, maybe you'll find it useful. Link in me signature.