CountA & CountIF using specific cells selection

I'm working on a sensitive document, so I'll try and explain my issue as best I can. I didn't create this document myself - the company I work for has asked for a modification, and if I can figure this out it would go a long way to completing that modification.

There's 2 columns;
A - will contain a 1, 0 or x depending on responses elsewhere
B - will contain a comment based on responses elsewhere

It uses this formula to create a score for the section;
=COUNTA(B2:B20)-COUNTIF(A2:A20,"x")

What I need is a modification to the formula if, for example, rows 4-8, 11, 13 and 18-20 were not required for a specific customer. So the formula would only contain (from both columns A+B) rows 1,2,3,9,10,12,14,15,16,17.
I can't simply delete or reorder the questions for a number of reasons - namely how they relate to other sections of the document and how it gets imported into our software - and that the same template is used for multiple customers and it's only specific ones where this difference is required.

Our software can hide the questions from view - however it will still take the score based on all questions.

I've tried just selecting the relevant cells, but I get the "too many arguments" error.
I've also tried the formula like this;
=COUNTA(Range2)-COUNTIF(Range1,"x")
Where range 1 & 2 are the required cells from each column. It worked with just Range 2 - i.e. =COUNTA(Range2)-COUNTIF(A2:A20,"x") although I don't think the score was accurate. When I put both Ranges in I get "#VALUE!"

Your formula does not give the required result.

There are no completely irrelevant questions, only occasional ones. These will not been hidden within excel but within our system - the excel document is run through our software and a report is created for the customer. As this is the main template I cannot edit the positioning of any of the questions because they will all be needed for other customers. I can not rearrange the order of the questions so I can simply select the range required, as this will affect the other pages of the document (over 70 pages within the document with multiple formulas back and forth between them all)

Is there another column that can indicate which rows relate to the particular customer?
Look at it this way.
In your mind, how do you determine which rows should be included?
The ones with the customer's name in column D ?

Whatever logic you use to determine in your mind which rows should be used, can probably be used in a countifs formula.
Something like
=COUNTA(B2:B20)-COUNTIFS(A2:A20,"x",B2:B20,"customername")

Never mind I've figured it out - it's so simple, I was trying to make it too complex.
Just need to create a list of required responses from columns A and B in an empty part of the page, where they all line up and I can use the original formula.

Thanks for trying at least.

@ Jonmo1
There isn't another column - the document is approx 10 years old, and this amendment has only just become required from a customer who has had this document for the past 10 years.
The questions to ignore have been determined by both them and us in meetings - for the moment they're just highlighted to show which ones they are.