Low ambient RH's, caused by AC in the summer and heat in the winter, can really drop the RH in your humidor. With an ambient RH in the 40's, that puts the pressure on the humidor seal and humidification device.
If you know your hygrometer is accurate (tested) and that you can trust it, I'd put a shot glass of distilled water in the humidor until the RH comes up to where you want it. When I had a desktop, I'd do that every winter when the forced air heat came on and the ambient RH dropped like a rock.
Lastly, a word about storage RH. Round up a hundred experienced cigar smokers and ask them what their preferred RH is. You'll get answers from 58 to 75+% RH. It is most certainly personal preference. Most guys will run between 60 and 70% which is where 65% came from. Anything above 70% and the risk of mold goes up exponentially. But, make no mistake, it's personal preference and only that. Run things where you like them.