Because, as HELP explains, ADDRESS() returns a text string, not an address. INDIRECT() converts a text string into an address.

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Kind regards,

Niek Otten
Microsoft MVP - Excel

"Dave F" wrote in message ...
| =ADDRESS(8,MATCH(AO5,Z5:AK5,0)+25)) returns AK8.
|
| =T8-ADDRESS(8,MATCH(AO5,Z5:AK5,0)+25)) returns #VALUE!
|
| =T8-INDIRECT(ADDRESS(8,MATCH(AO5,Z5:AK5,0)+25))) returns the
| appropriate calculation.
|
| Why?