It doesn't really matter where you align the guage to on the thread but the points should align at exactly the same position on each thread. In the photo it clearly shows an increasing misalignment with each consecutive thread. Obviously it's far better/easier if you have the proper thread form...
That doesn't look to be matching the 3.0mm pitch guage to me. The points of the guage need to be slotted into the thread grooves rather than the top of the thread.