Ok, so based on your conditions, I would say yes, 340 to 380 miles is more like it. More like 350 or lower though and maybe more like 320 to 330, because your combination of relatively high highway speed, and your use of the A/C. The EPA's ratings usually go off of a 55 to 65 mph speed on the highway. Believe me, I know how hot Texas gets lol, especially with the glass roof! One tip I would give, is to the leave the recirculation on as much as possible. This increases efficiency, and will make a notable difference in range. Hope this helps!