I own some land in west Texas, and the seed I use says the same thing. We actually spread the fertilizer first and did one more light till/smoothing of of the soil. This let the fertilizer be rotated into the ground. We then spread the seed according to the depth needed for the seed itself. This was done on the same day, we just did not do it at the exact same time.
A couple of things to keep in mind:
- Plant when their is some moisture in the soil. Really dry is bad,m as the seeds need some type of moisture.
- Try to plant a few days before a good rain is coming. Rain is everything.
I am sure you already new this, and in east Texas is should not be a major hurdle to keep the soil wet.
Good luck!