Ah, got it, thanks. I think I also screwed it up by trying to be too cute.
I was running some absurdly conservative scenarios for DW. I was showing that we still had a great prediction of success even if we decided to buy a very expensive house in 5-10 years time. Because we'll be retired with no documented source of income, I'll assume we're paying cash, and took a large chunk out on the spending tab. (In real life, we'd never do this, but I was trying to prove a point to DW...)
By shortening our life spans 10 years, I think I reduced the number of years to remake that money spent on the hypothetical house, as otherwise annual spending should be far less than returns. It didn't affect it greatly - I think it went from 90% to 87% when we died at 90 instead of 100, but it was curious.
Anyway, that all makes sense now. Thanks.