Sum If and Grouping Dates

Certainly but the advice was not based on ignorance of alternatives

=SUMPRODUCT(--($A$2:$A$20=$A27),--($B$2:$B$20=$B27),E$2:E$20)

Used in volume or with large ranges performance will be affected.


EDIT: re: your question regards use of colon delimiter - as a general rule by adding a delimiter you reduce risk of false positives... eg:

A1: App B1: le
A2: Ap B1: ple

Ax&":"&Bx -> App:le / Ap:ple -> not same
Ax&Bx -> Apple / Apple -> same

Simplistic example (and use of : is risky if only dealing with numeric columns for ex.) but you get the idea.