The main shutoff on my tank doesn't shut off all the way as I discovered when I replaced my cook top. I'd suggest that you verify that there is no flow of gas from the supply lines as you disconnect the appliances. I bought a plug to go into the cook top supply line.
You can bleed off the gas in the tank by connecting an a lp powered appliance (gas grill, heater, etc.) and leaving it fired up until it goes out. That's how they do it at the RV place I take my rig to.
If you want others to be happy, practice compassion.
If you want to be happy, practice compassion - The Dalai Lama
1984 310 Limited Motorhome
Courtesy Parking (W/S/E/Wi-Fi) on I-5 in Northern California, 70 miles from Oregon border