I'm approaching 5k miles on this OCI in my Civic in my sig with Ultra and a Honda A01. This is the car's first time with synthetic in the sump to my knowledge. Has 40k on the bottom end of the block and 118k on the cyl head. My driving is basically 70% highway and back roads. Should I change it soon or is it safe to go a little longer? Also contemplating whether or not to leave the A01 on again for another OCI.