If some site have both affiliate PPS ($ per signup) as well as Partnership (% on recurs) mix the two codes so some would sign up for the recur (which would take longer to get a check) but if someone signs up via the PPS link you get a boost. The customer doesn't know which one it is and you can use an ad manager like OpenX (or whatever it's called now) to just cycle through them.

Plus if you need a boost to get you over the line, schedule them all as PPS for a few days to bump your totals.

Of course you lose the PPS recur but may be an option since maybe they cancelled after the first month so you're ahead anyway!