Help needed! Referencing multiple excel worksheets in a formula - Microsoft Community

i trying check line confirm summary numbers below correct work.

this needs work on variable number of worksheets worksheets data on them set between blank beginning , ending tab. range of worksheets a:z!. , data on numbered sheets between two. 

i have tried 3 main ways countless variations far. 

=sum(a:z!ai4)-sumif(a:z!ai4,a:z!$h$1="mtm")  the first part works section condition not - return #value 

i repeated if statement sum in , ended #ref error.

i tried

=sum(a:z!ai4)-sumif(indirect(a:z!&$c$168),"mtm",a:z!ai4) c168 refernce cell h1. 

i use last section of summery sheet needing completion. tried indirect many of other formulas on sheet require work ex)=if($a14<>"",if(indirect($a14&"!"&$c$168)="non-pfic",indirect($a14&"!"&k$167&"4"),""),"")

you need have names of each worksheet referred in formulas. having variable amount of worksheets referred in formula won't work.

that's why formulas giving errors.

Office / Excel / Other/unknown / Office 2016