Allow Multiple Quantities setting must have added tick option to create only one service.
Let me explain this to you,
When a customer orders 100 Gig from our product of 1 Gig extra with the Allow Multiple Quantities enabled on the pricing TAB of the product setup, the system will create 100 services on the customer account, one for every Gig he ordered.
This is excellent if its normal services like hosting or Radios but when its 100 gis of space and you have 100 services created client side it can get messy.
I am suggesting, a TICK on the same pricing tab, just under the Allow Multiple Quantities TICK to allow you to tick it to create only one service from the Allow Multiple Quantities choice option from the customer when ordering.
Hope I made my self clear ,,, if not please ask me to elaborate more if needed, as I am sure many people are struggling with this like we are.