Multiple IF/IFERROR statements, resulting in "too many arguments" error

Hello,

I have a formula that works just fine now, but when I try to add another IF statement I get the "too many arguments" error. The working formula is:

{=IF($D14="",SUMIF($A:$A,$B14&MID($C14,1,SEARCH(" Total",$C14,1)-1),F:F),IFERROR(ROUNDUP(INDEX(Forecast!$A:$J,MATCH(1,(comparison!$B14=Forecast!$A:$A)*(comparison!$D14=Forecast!$C:$C),0),F$1),0),"Not On Plan"))}

the extra IF statement is: =IF($C20="",SUMIF($B:$B,LEFT($B20,LEN(B20)-6),F:F)/2)
I tested this out alone and know if works.

This is how I tried to combine them:
{=IF($D4="",SUMIF($A:$A,$B4&MID($C4,1,SEARCH(" Total",$C4,1)-1),F:F),IFERROR(ROUNDUP(INDEX(Forecast!$A:$J,MATCH(1,(comparison!$B4=Forecast!$A:$A)*(comparison!$D4=Forecast!$C:$C),0),F$1),0)),IF($C20="",SUMIF($B:$B,LEFT($B20,LEN(B20)-6),F:F)/2),"Not On Plan")}

Perhaps I am misplacing parentheses or something. Any help is appreciated!

Try

=IF($D4="",SUMIF($A:$A,$B4&MID($C4,1,SEARCH(" Total",$C4,1)-1),F:F),IFERROR(ROUNDUP(INDEX(Forecast!$A:$J,MATCH(1,(comparison!$B4=Forecast!$A:$A)*(comparison!$D4=Forecast!$C:$C),0),F$1),0),IF($C20="",SUMIF($B:$B,LEFT($B20,LEN(B20)-6),F:F)/2,"Not On Plan")))