Value Error when calculating dates, IF Function & WORKDAY Function

[Chris_Mercer]

Hi - I'm getting a value error returned when trying to calculate dates in a formula and am looking for help.

I'm looking to calculate a series of procurement dates (shipping, manufacture etc.) which subtract duration days from previously calculated days. This depends on whether the materials are being purchased locally or internationally thus working with different holiday calendars (Tables 3&4 on another sheet).

The formula seems to work for the first column (AS) which gets the date from a VLOOKUP formula (in AV) but then returns an error in subsequent rows (AO,AK) when International is selected in column AH??

Thanks 

[#2]

Can you share a link to access the file ?

[#3]

@Excelonlineadvisor 

Hi File is here

P&FHF Subcontract & Materials Procurement Schedule MS Project 24.01.11.xlsx

Thanks

[#4]

Pls check the formula at AO9

Current Formula = =IF(AH9="International",WORKDAY(AS9-AN9,Table3),WORKDAY(AS9,-AN9,Table4))

Correction :- Instead of WORKDAY(AS9-AN9,Table3) , it should be WORKDAY(AS9,AN9,Table3)

[#5]

@Excelonlineadvisor 

Hi  Thanks for the help - yes that clears the value error when I amend the formula to WORKDAY(AS9,AN9,Table3)... but that adds the number of days to the previous date whereas I need to subtract the dates back from the previous i.e. AO12 subtracts 5 working days from AS12 date to return the earlier date.

Weirdly when I re-entered the original formula into the cells with the minus sign the value error cleared??

Appreciate your help