I think your maths must be wrong. This 27 per 1000 for 4 weeks seems much lower than on offer from minnowbooster.
There better offers than the ones in the photo below, but you can see that 35 steem is on offer for less SP. Offer 40 and you will get takers.
it must be offer for very low power
These offers are for 1000 sp just like yours. You can see it in the photo above. There are 10s of offers at the same level. There may be some minnowbooster offers similar yours, but most are much better deals even after the 10% they charge.
hmm but actually these days it is useless to buy power on high rate due to market crash it is not even possible to recover the fund