Somehow posting is magical- if I find the answer myself at all, it is always
right after I post :-/

Instead of trying to affect the array value, I just pushed the value to the
other side of the equation:

IF(Total04!E$6:E2000+10=B4,1,0)

became

IF(Total04!E$6:E2000=B4-10,1,0)

and of course now it works perfectly [sigh]

Sorry for the bandwidth on the original post!