I think you are teaching them responsibility. If your son enjoys splitting then by all means allow him to do it. I take it you taught him safe use of all the tools so really there is no danger.
Chores are a must, in most cases people are awake 16 hours of their day, if the kids were doing chores for most of them then that would be an issue. An hour or two a day is not a lot of time for them to help contribute to the family's work load.