Yeah, it's not critical--if you use too much it doesn't seem to affect the ability of the titration fluid to give an accurate reading.

I've been using it for years and you only need enough to turn the water nicely pink, no more. If it's less than two scoops, fine.

However, if you have NO chlorine, it won't turn pink at all. This is a good time to double-check with a standard OTO test kit. Ben's pH test cell also has the OTO test for chorine.