I went through the pvr.iptvsimple documentation where it says:
After adding and selecting new config files you will need to clear the EPG cache
Settings->PVR & Live TV->Guide->Clear cache
for it to take effect in the case of EPG relatd config and for channel related config will need to clear the full cacheSettings->PVR & Live TV->General->Clear cache
.
It seems I need to do it only once after updating the EPG url.
Thanks for the help.