Your premium has a mode: annual, semiannual, quarterly, or monthly. The annual premium is the base number. Every other mode is that number multiplied by a modal factor, and the factor is always above the simple fraction.
Two reasons for it. The carrier gets your money later, so it loses the earnings on the float. And more frequent billing means more billing, more lapses, more reinstatements, more administration. Those costs get priced into the factor.
The ordering surprises people. Annual is cheapest. Monthly bank draft is usually next cheapest, because automatic drafting has the lowest lapse rate and carriers price it accordingly. Quarterly and semiannual often cost more than monthly draft, and monthly direct bill, where they mail you a statement, is frequently the most expensive mode on the sheet. So the middle options can be the worst options.
On a high cash value design this matters more than it does on a term policy, because the difference isn't just cost, it's contribution. A dollar that goes to modal loading is a dollar that never reaches your cash value, and you're compounding that shortfall for decades.
Ask your agent for the annual premium and the modal premium side by side, then multiply the monthly by twelve and look at the gap. On some contracts it's small enough to ignore. On others it's a few percent a year, which over thirty years is real money out of the cash value column.
If your cash flow can't handle an annual payment in one hit, monthly draft is a fine answer and I wouldn't twist anybody's arm about it. What I would do is set aside a twelfth of the annual premium each month in your own account and pay annually out of that. Same cash flow, and you keep the loading. And if you're already changing the mix between base premium and paid-up additions, that's the moment to fix the mode too, since you're reissuing the billing anyway.