fresh start with MDBT42Q , some specs before start toe code

Great, this looks good!

I can see the data is changing when I send something to the device but is there a function I can call to update the value only after the data is change? and not print it once every 1000mSec (like I did)?

There's nothing built in (often you may want to be able to send the same number twice). But it's easy enough for you to add code like if (value!=lastValue) ....

BLE Connected, queueing BLE restart for later

No, this is fine. It just means that Espruino can't change the advertised services when you're connected to it. The second you disconnect it'll change them and all will be fine