Hi @HeMan,
I have solved my problem on the timing somewhat if you want to have a read here .
I was just sharing what I had done and tried as some of it may solve your problem. The reason I suggested using CRC15 was that on the z-wave allaince website here it mentions that CRC16 Encapsulation command class is compatible, I wasn’t sure if the the securityV1 was. Looking at the user manual however now though page 48 both methods are supported and work fine.
I am going to develop the device handler a bit more first and then I dont mind sharing with you if it actually works and the issues I run into, it seems to be a bit of a learning curve getting used to it.