Just to clarify - not sure this was detailed in the thread and maybe you learned already: When you sync and over-write your mobile dB, you download the server set of data - it does not merge. If you sync without over-write you're updating the server with whatever is on your mobile device.
My recommendation: Before altering your humidors via a mobile device, always sync with full over-write. After you make edits sync again (without over-write) to update the server.