Hi,
I don't know why you would configure more license if you have less products. But you can do it if you want.
If the product does not have any stock, you can't buy it. It's a fact which would not change.
If you have less serials than products, you will receive a notification message because the serial association will failed.
You can receive a notification before, with the great stock notification option in the packs.
After that, you can link the product stock quantity with the serial quantity in a pack. Once again, a quite useful option in the packs.
Regards,
Jerome - Obsidev.com
HikaMarket & HikaSerial developer / HikaShop core dev team.
Also helping the HikaShop support team when having some time or couldn't sleep.
By the way, do not send me private message, use the "contact us" form instead.