When it comes to pitra dosh. One has to honor the acentors. It doesn’t have to be with shani…its completely different. Shani has nothing to do with the conjunction sometimes so doing Shani pooja is not something you should do
Pitra dosh form when sun and moon with the effect of rahu is combined. People need to check this to determine their dosha. Then you can perform it. Performing something that is not written in our chart can do something not good for us sometimes. So be careful