I just bought the Dolphin Diagnostic and I too at first was not sure if something was wrong with it.

My pool is a double round like a figure 8 with a sharp transition from the deep to shallow end. After the first run I found it only got the deep end and maybe 10% of the shallow. Called technical support and hey told me to place the handle at max position opposite each other and move both of the floats to the side of the power cord. This 'seems' to have worked for me. Put it in last night at 7:00 and this morning it looks like it covered most of the pool 90-95% or so. Technical support also informed me that the Dolphin does not always try to reach the waterline. Sometimes it will only go up partially then quickly reverse, this according to them is normal.