Yeah, I noticed that, too, and it seems like $150 can include the tax. Hoteltravel.com seems to be part of an Indian online travel agency group. It gets more than its share of negative reviews, but seems to be a "legitimate" company, with a billion market cap traded on NASDAQ (ticker symbol MMYT). Here's a tripadvisor discussion on them, where a company rep steps forward to help a customer:

http://www.tripadvisor.com/ShowTopic..._com-Bali.html

So for the "right" booking -- basically one that comes in right over $150 -- I think it's probably worth taking a shot with them. FWIW, I couldn't find any additional cashback to use.

EDIT: Well, I just made my first booking with them and while I haven't yet called the hotel to reconfirm, the process seems to have gone smoothly. As I mentioned, they allow you to include the tax in the $150, so with many hotel taxes in the 10 to 15% range, you can often book a hotel in the $130s and get your total room cost down to $100. And you can book multiple nights individually. This is a particularly good deal when you're hunting for deals in more expensive hotel cities or at 4 and 5 star hotels.

BTW, the company seems to be based in Thailand, even though it's owned by an Indian corporation. It also seems to have been founded by Westerners. Whatever -- as long as the reservations are honored.