Can see already the above will not work for tickets because as author has in readme notes


" if you want to allow customer to purchase more (e.g. maximum of 3) copies of that voucher, you will need to generate a 3 separate downloadable products, and e.g. call them '10$ voucher link 1', '10$ voucher link 2' and '10$ voucher link 3'"


Selling tickets obviously people will buy more than one when it is for children- usually a family of at least 3 or 4.