2 weeks is too short of a time to make sticks 'crunchy' in a ziploc bag, let alone an 'underhumidified' humidor.
If you get it to 70%, how much higher do you want it to get?
60% is not too low. Many will have humidors that hover in the 60-65% range and prefer it as such.
You admit that your hygrometer may not even be properly calibrated, so until you know how far off it is, you really can't get a whole lot of help.
Just relax, cigars are relatively forgiving with humidity swings.
