If I am wrong on this, I am sorry but from reading your post, it sounds as if you expect the image at the bottom of the ground glass to remain in focus as you tilt the lens.
Most view cameras (the Sinar P is the only exeption that I am familiar with) tilt (and swing) on a central axis, so as you tilt the lens board, both the top and bottom will be thrown out of focus. A series of focus adjustments are generally neccesary.
Don't worry, as you become more used to it, you will be able approximate your tilt beforehand based on the angle of the GG to your desired plane of focus leaving you with only the fine adjustments to make while under the dark cloth.

Best of luck.