far better to use too much oil , than not enough!
It's true that it will be a teeny-weeny bit to rich in oil, but not by a great deal.
The guys at work tend to run most of their equipment with a bit too much oil, because they are using the stuff for many hours each day, they tend to get several years worth of domestic use in one season of professional use. all our seizures, are caused by overheating, and not by lack of oil (unless they do just put neat petrol in them by mistake)
you might find that the engines use a plug or two extra, over their life time, you might also find that they need their air filters changed/cleaned a little more regularly, and the worst case scenario, would be that it could need a decoke sooner., but it really does depend on how much you are using the equipment, what the equipment is, and where it was made........... (regarding machine life expectancy
)