The money balance is the total amount of all the money currently circulating in the whole society-surplus refers to the part that remains circulating in the society after banks create or recycle money.

Examples of banks creating or recycling money: the central bank puts in/recycles base money, and commercial banks create broad money through loan-to-deposit ratio.

M/P is the currency balance after price correction, excluding the influence of inflation, so it is called the real currency balance.

I hope it helps.