Extend formula range dinamically while using an array ?

Hi,
my first post here :-)

I have a table with resources, days of the month and hours logged by each one of them for that specific day.
On top of this table I have an index that identifies if that day is a BankHoliday of Location1/2 or Location 3

The formula below highlights if someone has logged less than minimum contractual hrs (8 for location1/2, 9 for location 3) for the dates between cell "O18" and "AS18".
All works fine, but I want that formula to limit its range up till the date I want to monitor - so starting in "O18" but ending in column "XX18" where "XX" comes from another condition.
I tried using INDIRECT referring to a value listed into another cell that has the "XX" value instead of "AS18" but the formula returns an error.
Is it there any limitation into using INDIRECT into an array formula?

{=IF(OR(G18="Condition1", G18="Condition2"),
IF(SUMPRODUCT(IF((O18:AS18)<9,1,0),IF(WEEKDAY(O$6:AS$6,2)<6,1,0),IF(O$6:AS$6>L18,1,0), IF(O$6:AS$6<M18,1,0))>0,1,""),
IF(SUMPRODUCT(IF((O18:AS18)<8,1,0),IF(WEEKDAY(O$6:AS$6,2)<6,1,0),IF(O$6:AS$6>L18,1,0),IF(O$6:AS$6<M18,1,0))>0,1,""))
}


Thanks in advance for your help.
Andrea

thanks both for your replies. Sorry for my belated update.

I've managed to solve my issue adding another "index" row that fires "1" if the correspondent date is less or equal to the selected max date in a specific drop down menu or 0 in the other case.
This way my check works only till the column where that index = 1.

Cheers,
Andrea