Spacing issues with align, aligned and intertext

I have the following snippet:

begin{align}
    begin{aligned}
        ab &= abcdefghij&&ABCDEF 
           &            &&-ZYXW
    end{aligned}
    intertext{not also that}
    ab &= defghijklmn
end{align}

This has a few spacing problems. First, there is the gap between j and A and in the next line before the -. Second, the second equation is misaligned. It should have been aligned at the = of the first equation. How can I fix this?

documentclass{article}
usepackage{mathtools}

begin{document}

begin{align}
        ab &= begin{alignedat}[t]{2}
            abcdefghij&ABCDEF 
           &-ZYXW
           end{alignedat} 
    shortintertext{note also that}
    ab &= defghijklmn
end{align}

end{document}