Maybe I'm not interpreting your reply - subscription of devices does not impact this at all. One can use the 740 and iFly iOS device connected to the Statux simultaneously. Either way, my 740 drops WAAS & GPS every couple of minutes even being the only device on. This issue just started back in August.
Edit: re-read your suggestion and take it as review the 740 WiFi devices and delete all others. I'll try that.