I wasn't sure by what it meant ramp up. So essentially pay is held until this time frame has passed?
Whats the point of a ramp up period? It says to reduce variance but how does it accomplish that?
Payment per block is paid according to the number of shares you've sent to the pool over 5x the current difficulty.
At current pool hash rate and network difficulty, this works out to all the shares you've submitted over the past 13.5 days.
The reward you get is then (Your Shares) / (Total Shares submitted to pool over 5Nd) * (Block Reward + tx fees) - 0.9% Pool fee.
So, if you pool hop during the 5Nd period, you're submitting fewer shares to the pool compared to people who didn't at the same hash rate.
Edit: This is aimed at reducing pool variance by discouraging pool hopping.