Saved Search sorting Formula (Numeric) columns

Hi Everyone,

I've just come across an interesting glitch (I think) with my saved search. I have two Formula (Numeric) results columns but can only sort by one of them when view results.

These are my result columns:
Formula (Numeric) -- Sum -- CASE WHEN {custrecord210} = 'Gallons' THEN {custrecord215} END
Formula (Numeric) -- Sum -- CASE WHEN {custrecord210} = 'Pounds' THEN {custrecord215} END

The columns check if the sale in the custom record is in pounds or gallons and sums.

What's strange is that I can only sort by whichever Formula (Numeric) column comes first in the list of result columns. I can change the sorting from ascending to descending on one but whenever I click the column header of the other, it only changes the sorting of the column that comes first.