What bot are you running?
We run two passes (5 ips at 12000 RPM's with a 1/4" downcut or compression) in mdf, one climb at .73 and a clean up final conventional at .755 and ,while your RPM's are lower they are within the right (all be it higher chipload), that said we never have wander like that.
You might want to check your bot out.
Kyle Stapleton
River Falls Renaissance Academy
Math/Technology Education Teacher
PRS Alpha 96x60 2.2 hp spindle, Double Air drills, 6" indexer, Fein 5 zone vac table
Desktop w/spindle
Potter Pen
Aspire 8.5, Creo 3.0