I don’t think that a “small” amount of overfilling oil will do any damage. The problem is that all engines are not the same. If your daughter experiences oil leaks then her engine is probably suffering the effects of overfilling. I personally never overfill anything because there is always a chance of doing damage. Is your daughter going to a real mechanic or to one of those “quickie change shops”? There are no mechanics at a quickie shop so they should always be avoided. No filling, underfilling and overfilling are their specialty.