The problem is your builder installed a cheap-o builder grade toilet. It is pretty standard procedure with builders to use the cheapest toilet and other appliances in order to keep the selling price down and their profit margin up. There is nothing wrong with the drain, it is the toilet that is at fault. MaP ratings are over emphasized. Any thing above 500 is considered just fine, but the problem lies in the internal design of the toilet. You are right about getting rid of the Charmin paper. It has a high cotton content and does not flush well. I have found the house brand paper in supermarkets to be just fine. Safeway calls theirs Softly, but I'm sure other chains have a similar paper under their house label. I and many of the regulars on this forum feel the Toto toilets are superior both in flushing performance and in quality workmanship. These are not found in discount stores, but they are competitively prices with American Standard, but AS and Kohler are not generally advised for reasons you can research elsewhere on this forum. I'm sure you can find Toto toilets in many plumbing shops in Houston. Toto is the world's largest manufacturer of toilets and they are very well respected in the industry.