Counting Varies Depending on Multiple Choice Selected

Yes, I tried but, I may be doing something wrong.  It returns this error.  I thought maybe because it is not expecting the multiple choice textlist?

Because you are using a text list, you have to do some mapping.
Try this:

var number a = if(contains([Tubs Needed], "A"),1,0);
var number b = if(contains([Tubs Needed], "B"),1,0);
var number c = if(contains([Tubs Needed], "C"),1,0);
var number d = if(contains([Tubs Needed], "D"),1,0);
If(
    contains([Tubs Needed], "NONE"),0,
    $a + $b + $c + $d
)

GENIUS! That worked :)
Thank you so much, especially for your patience!