Related question: How should I factor in the pension when determining what my FI number is?

A non-inflation-adjusted annuity doesn't quite fit into the framework assumed by the Trinity Study folks, due precisely to the lack of inflation adjustment.

Taking a deduction from annual spending and using 25-30 times (actual spending minus annuity) isn't exactly correct because the annuity becomes a smaller fraction over time.

Treating it as part of net worth isn't exactly correct because it won't appreciate in value as a stock & bond portfolio would.

One can always make some approximations, e.g., use (expenses minus "annuity payment discounted by 10 years of inflation") or "use a lower assumption for total stash growth" in the pertinent equation:

Time in years to FI = Ln((S + i*E/WR) / (S + i*A)) / Ln(1 + i)

A = Asset amount currently invested in funds you will draw upon in retirement.

E = Total (including taxes) annual expenses in retirement

i = Return on invested retirement funds.

S = Annual amount invested in funds you will draw upon in retirement.

WR = Withdrawal Rate planned for retirement, using Trinity Study definitions.

Or go whole hog and stick everything into

www.cfiresim.com and let it handle the inflation effects. Just know that whatever calculation one does is likely to be wrong, so treat these as "guidelines" not "rules".

As for the primary question, I'd guess that not having to repay much of the loan would be financially better than having to repay it. You might throw the scenarios into Excel, however, to verify that - it's possible that delaying payments would cause you to pay enough more in interest to make that worse.