Lease extension offer-Ward Co. TX

I have received a lease extension for Section 226, Block 34, W/4 in Ward County, TX and Sullivan Land Resources is offering $600.00 an acre with 1/4 royalty. Wondering if this is a fair price for this area. The last time I received an offer from them- a week later I got a call from a landman offering me a lot more money but I had already signed the contract with Sullivan. :(

Bonus is low.

We received $2200 an acre for a small parcel in Section 201 Block 34 in Ward County in November 2012.