That is a moderate amount of IP creep. If it happened immediately after a rebuild, I'd probably take it for a dive, or maybe leave pressurized for several hours, tapping the purge a few dozen times every so often, to see if it breaks in and seals better. But if this is happening after a few dives, then it means something is not quite right. It could be that there's a small flaw on the piston edge, or maybe an imperfection on the seat. You should also check IP at various tank pressures; the way to do that without having multiple tanks around is simple. Start with a full tank, pressurize, then shut the valve off. Then tap the purge and you can watch the SPG fall to whatever supply pressure you want. The reason for this test is to see if the creep is less with low tank pressure. If it is, then that could indicate a too soft or poorly lubricated HP piston o-ring. Sometimes increased friction at that o-ring causes the piston to lag just a bit in locking up and there's your creep.
Unfortunately the practical answer is that you need to have someone who really knows what he's doing service the reg and get rid of the creep. SP doesn't support the idea of polishing the piston edge with micromesh, but I do it all the time on these rounded edge pistons and it really gets rid of creep. A tiny nick or bit or glaze on the piston edge, smaller than anything you can see with the naked eye, can cause this kind of creep.
If you want the other opinion, there are plenty of dive shop techs that would say this is fine; it's not continuing to creep out of range and it won't affect performance of the reg, and that's sort-of true, but to me, anyhow, I don't tolerate any creep in my regulators, because I don't ever ever want to worry about a first stage creeping badly in a cave, especially one that I'm not breathing on every few seconds, like an inactive tank in doubles. So I fix it using micromesh on the piston, being very picky with the seats, making sure I use a 90 duro o-ring for the HP piston, and making sure there is plenty of lube on the o-ring and piston shaft.
