In All Seasons Window and Door Mfg., Inc. v. Red Dot Corp., 181 S.W.3d 490, 498 (Tex. App.--Texarkana 2005, no pet.), the court addressed the proper interest rate to be applied to a contract that did not specify the interest rate to be charged but instead provided for interest "at the maximum rate permitted by law." Id. The court concluded the language "maximum rate permitted by law" was sufficient to support application of the 18% minimum ceiling rate under section 303.009. Id.