Dear Student
Closing balance of profit and loss account is the balance which is left over after any appropriation or transfer to reserves.
Yes, It may include the leftover balance of previous years profit as well.
i.e Suppose Current Year profit = 1,00,000/-
Opening balance of profit and loss account = 2,00,000/-
Transfer to Reserves = 75,000/-
Therefore closing balance of profit and loss account = Opening + Current year profit - Transfer = 2,25,000/-
Hence it included previous years profit as well.
Regards