Exactly that, its the perfect balance to minimise breakages especially for those who are new to length. You can always elongate the nail bed with a coverage pink for a sleeker look but the extension free edge shouldn't really be longer than 50% of the natural nail bed.
Those who have worn them for longer will get used to the extra length and you can move the apex back to compensate as they become more accustomed to them but for newbies you're in charge, you're the trained professional who knows her job.
If they insist on too much length then make a note of your recommendations and waen them that repairs and breakages must be paid for