@minnowbooster I'm sorry because I ask you this on an unrelated post but I think the DLM doesn't show an accurate APR for delegations. They're higher than they actually are. Here are two examples:

delegation of 150SP for 1 week with 0.9 STEEM payout says it has 18.7% APR

I use the following formula to calculate APR:
Payout/((Week x 7)+Cooldown) x 365/DelegatedSP x 100%

so, for that delegation request it would be:
0.9/((1 x 7+5)) x 365/150 x 100% = 18.25%

Here's another example:

According to the formula before The APR would be:
24/((4 x 7+5)) x 365/1500 x 100% = 17.67%

The two examples to are to prove this is consistent on all delegation request regardless of duration and amount of delegation.
I tested the same formula on @delegationhub and their APR shown on lease requests are consistent with the formula.

I don't know if this is a mistake or you simply use different formula to calculate your APR. If you do use a different formula i'd like to know the formula. Thanks!