So would I, normally, but that is OK only if doing nothing but short local flights.
Let's say I am off on a trip to Greece, which is c. 20hrs airborne time. If the oil is at 40hrs, that will push it to 60, and I know from oil analysis experience (having once gone to ~55) that the oil will not be working at all well at 60hrs.
It's OK to do it occassionally, obviously (and it is possible legally on an N-reg) but if one keeps doing it, IMHO the eventual result will be a knackered engine.
I use Shell 15W/50, have done experiments alternating between that and Exxon Elite, and could not see any significant difference.