Checkbox binary giving me delimited string

I may be really misinterpreting here, but from what I read, checkbox multiple values binary works this way:
box1=1
box2=2
box3=4
box4=8

If you check box 2 and box 3, the value of the checkbox field is 6 and that is what should go in the database. Instead I am getting 2:4 as if it were a delimited checkbox with a semi-colon delimiter. Did I miss something or does this simply not work?

Edited to add: I understand you can loop a foreach to get the total, but from the documentation it looked like that was done for you. Apparently the only thing binary does it assign the values 1, 2, 4, 8, 16 ad nauseum. Possibly just misleading documentation.

I just did a quick test and it works correctly for me. Here is the debug after I selected options 1, 2 & 3. (=7)
UPDATE membership_level SET option = ‘7’,

So it actually puts 7 in the database without you doing a thing. That is what I hoped it would do, but on mine…hope. I get 1;2;3 in the table. I’ll set up another test bed with another database table and see what happens, but mystified. Thanks for checking.