Check a parameter value in SRPOC

[angelica]

Well,

I am going through one of my SRPOCs and I have some doubt about one of its values. It goes like this :

Update tb_book

SET stockbalance = stockbalance-@qty
LimitAlert= Case

When stockBalance-@qty<re_orderLimit

THEN 1
ELSE 0
END

Now my question is:

Is @qty being deleted twice , in the Set... and in the When.... ?