General question about Rentals

I'm looking at some rentals for next summer. I normally use a travel agent and she has sent me some houses that I like, however, prior to enlisting her help I started some solo research and amazingly enough had settled on a couple of the homes that matched the ones she sent to me as options.

I used Twiddy for my search.

My general question is this...I am seeing some pretty significant price differences between listings on Twiddy and what she is quoting me (the agent prices are higher). Does Twiddy have some hidden catch in their displayed pricing where it is quoting a lower price and not including something?

I am talking 2-4k deltas for the same properties on the same dates.