same trouble here: with my moto G 2nd gen, and lollipop 5.0.2, i'm now unable to manage dual sim with go sms pro app : using the native sms/mms app, you can choose which sim you want to send each sms with, but if you try to switch back to another downloaded app, when going to "parameter", you have only these two options : "choose XXXnetwork every time" or "choose YYYYNetwork sim everytime".
WHERE THE HELL is the "ask every time i send" option gone ??????
Why can you get this option for the native app and not for all the downloaded ones? This is insane!