UET Taxilla admission Guidance

I've heard ke if you get selected in a program you have to give its fees for securing the seat and if you get selected in later list you can choose that option.

lets say I get selected for EE in like 3rd list, then I'll have to pay its fees, and if I get selected for Computer eng in the 6th list, and I'll be able to change the field. Otherwise, if I do not give the fees for EE and the deadline ends, then I will lose the seat and the chance for computer engineering?

lets say If i give the fees, will it be refundable in case I choose to go to another uni?