I used a pre-mixed mortar (unmodified) to lay porcelain tile in my kitchen. A mixed unmodified mortar was used under the hardiboard and it was also screwed down. The pre-mixed mortar stated for "ceramic tile" and this was not noticed until the job was completed. Since it is only my husband and me in the house, there is not any heavy traffic on the floor. What consequences should I expect for using the wrong mortar (since it is generally suggested to use modififed mortar for procelain tile)?