There are three reasons for thermal switch with lower temperature but higher price:
1. Thermal switches with lower temperature have to use some special materials, like bimetal strip and contacts. These materials have higher cost and better quality level;
2. In the process of manufacturing, both production and testing equipment for lower temperature thermal switches are different. The equipment cost of low temperature is higher than common temperature ratings.
3. The production yield of low temperature thermal switches is lower than standard temperature rating also. It would make the final cost is much higher.