It makes no difference in the macroeconomic sense when there are many overlapping loans, as there indeed are in the real economy. Let me try another example, where the bankers credits himself his profit as your loan is repaid. You pay your first installment. After each installment, he spends the interest you pay him and reloans the principal. In Douglas' notation, A are payments firms make directly to final consumers in the form of salaries, wages and dividends.
B are payments firms make to firms or equivalent entities, including government.
There are accumulating balances in both the firms and consumers sectors. A represents the rate of flow of purchasing power disbursed to final consumers. To their employees to be spent. Sure, the interest can be spent but not in the same cycle. Since they're always in debt, I'd say that money collected by government is disbursed to consumers within weeks if not days.