Query about custom fields – option groups

Dear support team,

I am using for select field the option group

{optgroup}% Discount per Sale (EN)|No % Discount/0,-5% Discount/-5%,-10% Discount/-10%,-15% Discount/-15%,-20% Discount/-20%,-25% Discount/-25%,-30% Discount/-30%,-35% Discount/-35%,-40% Discount/-40%,-45% Discount/-45%,-50% Discount/-50%,-55% Discount/-55%,-60% Discount/-60%,-65% Discount/-65%,-70% Discount/-70%,-75% Discount/-75%,-80% Discount/-80%,-85% Discount/-85%,-90% Discount/-90%,-95% Discount/-95%,-100% Discount/-100%{/optgroup}

But within listing it is not proper displayed it is “-25% Discount” displayed instead of just “-25%” what did I done wrong. Screenshot – https://www.screencast.com/t/5k3r3OkrPdfF

AND also for sorting if I use “0-100%” and want to sort from lowest to highest how would you do that

as the result is displayed (low to high) like that
0
-100%
-95%
-90%
-85%
-80%
-75%
-70%
-65%
-60%
-55%
-50%
-45%
-40%
-35%
-30%
-25%
-20%
-15%
-10%
-5%

instead of (low to high)
0
-5%
-10%
-15%
-20%
-25%
-30%
-35%
-40%
-45%
-50%
-55%
-60%
-65%
-70%
-75%
-80%
-85%
-90%
-95%
-100%

AND for price category display I use this

FREE/< Free,Inexpensive/>$,Moderate/>$$,Expensive/>$$$,Very expensive/>$$$$

and want to proceed with the sorting to be displayed from Lowest to high
Free
$
$$
$$$
$$$$

I am looking forward to your help.

Best, Alex