A family of Microsoft spreadsheet software with tools for analyzing, charting, and communicating data.
As far as I can tell, it should be
=INDEX('Enter PHS Rates'!$D$3:$M$189,MATCH(C20&$A20,'Enter PHS Rates'!$C$3:$C$189&'Enter PHS Rates'!$A$3:$A$189&,0),MATCH($G20,'Enter PHS Rates'!$D$2:$M$2,0))
confirmed with Ctrl+Shift+Enter.