Riddle me this, Batman (Responses from HVAC Techs only, please)

Why is there 20’ of 10” duct coiled up between the main return trunk and the return vent in the ceiling, when the vent is only a few feet from the trunk?

Details: I live in a house in SE Georgia (hot, humid). My 13 year old 2 ½ ton Trane unit has 2 return vents. Both are 10” flex ducts off the metal return trunk line terminating in ceiling vents. Return vent “A” is in one room 20’ from the unit. Return vent “B” is in another room 40’ from the unit.

Return vent “A” is only a few feet from the return trunk line, but installed with about 20’ of the 10” flex duct, which is loosely coiled in a big circle between the truck line and the vent. Literally four feet of flex duct would have made a nice sweeping connection.

Was this done to even out the pressure between the 2 return vents so they have the same “resistance” from the line (so they are both 40' long)?  To reduce noise? Because the installer had the flex duct in the attic and didn’t want to take it back down?

I’d appreciate your wisdom, and guesses!