Is it possible to post extra charge into Room/Folio, without editing/opening the transaction using eZee Absolute?

Yes!

Path: Login into eZee Absolute >> Cashiering >> Cashiering Center >> Action: Post to Folio >> Search >> Select Folio >> Type: Extra Charges >> Select Extra Charge >> Amount  >> Add.

Screen Shot 1: (Cashiering >> Cashiering Center )

Screen Shot 2: (Action: Post to Folio >> Click on "" >> )

Screen Shot 3: (Select Folio)

Screen Shot 4: (Type: Extra Charges >> Select Extra Charge >> Amount  >> Add)

Done.