can anybody help me with the following formula, i think i got some thing wrong

=IF([@Stock]<5000,([@Class]="Fast",10000, 5000),"0")

the logic is if the stock is below 5000 and the items is classified as a fast moving item automated order of 10,000 should be placed otherwise 5000 if slow moving item, and if the stock is above 5000 no need to place the order.

i hope i explained it well, thanks in advance

Usman