The men's 5k record is 12:37.35,
multiplying that by 10/9 gives the "equivalent" of a 14:01.5 women's 5k. The actual women's record is 14:11.15. Using the 45s/mile rule yes, you will get that a sub 15 5k is "equal" to the world record, but I specified that 45s is most accurate at the high school level and using 10/9 works better for elite athletes. I personally use 35-45 seconds/mile for high school but in my previous post I was looking at extremes.
Nothing as simple as multiplying by a conversion factor will be truly accurate. Additionally, a men's record and women's record are not necessarily "equal". But IMO it comes pretty close— that's why we call it a "rule of thumb", not a "precise formula".
I'm curious about the IAAF tables. For elite performances is one thing, but they seem off for slower times to me. Looking at HS outdoor 1600m times on athletic.net I found that a 4:59 1600 for a woman was "worth" about a 4:18/4:19 for a man. (4:18 by percent, 4:19 by number). IAAF tables say that a 4:59.90 for a woman is 914 points, or a 4:13.63 for men. So that's a bit closer.
It also depends if you are measuring by percent or number-- the top 100 women vs the top x% of women who run track, for example.
Men's records * 10/9 vs women's records:
800m-- 1:52.12, 1:53.28
1500m-- 3:48.89, 3:50.07
3k-- 8:09.63, 8:06.11
10k-- 29:12.81, 29:17.45
HM-- 1:04:52, 1:05:26
Marathon-- 2:17:43, 2:15.25 (mixed gender) or 2:17:42 (women only)
Clearly not perfect but it holds up reasonably well.