Modifying metrics equations with shortcut keys

I often define metrics for similar shapes with equations like “=o” “=H” and sometimes there’s a need to add something on top of that like “=H+10”. But then when i try to modify the “+10” value with the shortcut keys the obvious happens, the metrics goes out of sync because they don’t match the equation.

Wouldn’t it be useful if we could change the “+10” with the shortcut keys instead of typing it in every time? Of course there are more complicated operations than plus and minus; not sure what to do with those. In case where there’s only one operator maybe just leave the operator and modify only the operand; in case there are multiple operators maybe… don’t support this feature ;)?

I think it already worked this way at one point. It still does with incremental metric keys for automatic alignment (e.g. +=10). Thanks for pointing that out.