Thank you so much for trying to draw my attention to a miscalculation. But I can't reproduce your results.

Today @drorion got 24.951 STEEM and 4.179 SBD for delegating 71,825.134 SP

24.951 STEEM / 71.825134 = 0.347 STEEM per 1000 SP
4.179 SBD / 71.825134 = 0.0582 SBD per 1000 SP

Let's convert the SBD / SP to STEEM / SP. I'm using the factor 0.321, as specified above.
0.0582 SBD per 1000 SP = 0.181 STEEM per 1000 SP

0.347 STEEM per 1000 SP + 0.181 STEEM per 1000 SP = 0.528 STEEM per 1000 SP
0.528 / 1000 * 365 days per year * 100% = 19.27 % APR

So today's APR of @a-bot is 19.3 % APR

But noone wants to delegate for just one day. Therefore I am using an average of the last 28 days.

On 2019-05-02 @drorion got 32.027 STEEM and 4.366 SBD
If I repeat the calculations from above with these values, I get
0.446 + 0.061 / 0.321 =0.446 + 0.189 = 0.635 STEEM per 1000 SP = 23.18 % APR
@a-bot's APR on 2019-05-02 was 23.2%

You can see, @a-bot's APR is decreasing and an 28 days average of 22.8 % seems reasonable to me.
The average APR will propably decrease even more within the next days.

But yeah I was surprised myself about this huge APR. Seems like the owner of the bot returns part of his payments back to the bot. He's subsidizing his own bot and missing on a part of his earnings from his own Steem Power.