@blueberrybushes has the right framework. The pension is a guaranteed income stream. (To the extent of the ongoing solvency of the payer) It is the ultimate fixed income investment. This question is the same as the more-typical "when should I take Social Security?"
You can view this as income, to supplement your living expenses. Or, you could view this as longevity insurance, to give you money should your stache run out. In the latter case, delay it as long as possible; if you never need it, you planned your life well and/or got lucky. In the former case, take it when you need it.
Your initial approach is more like maximizing return, a common way to begin looking at it. If so, take your guess based on mortality tables or family history, and solve the equation.