Haven't yet had a good read through the link Dan sent me, but do you aim to increase your lifts by 2.5kg however many times you do them in the same week (try to increase squats by 2.5kg three times each week?), or 2.5kg for each lift 1 time per week?
Wow that sounds confusing. For instance, I benched 80, 80, 80. Does this mean on friday I should aim for 82.5, or leave that until next week to do?