Formula to Static Value

Dear All,

I have a cell (quantity) where I keep on changing the values so that this will be mapped to different sheets

Here my requirement is,

formula shouldnot convert to value (as I use this formula daily), but value should be static after re-writing the value in the quantity (as this shouldnt be changed once it is mapped in different sheets)

Ex: Please refer the attached excel file 2 Sheets.. When I enter quantity in Sheet1, it will mapped to certain cell under receipts column in sheet2 as per the below formula

=IFERROR(IF(AND(HLOOKUP(A$1,Sheet1!$E$1,1,0)=Sheet1!$E$1,HLOOKUP($A3,Sheet1!$E$3,1,0)=Sheet1!$E$3),Sheet1!$E$5,0),0)

But here challenge I'm facing is, When I enter quantity for present receipt, it is displaying the value but previous entered value is becoming zero which I should restrict not to happen

Please do the needful and if not understood my requirement please let me know