GMAT Strategy

I am so confused today... its really frustrating.

my scores of manhattan mock

mgmat 1 - 610
mgmat 2 - 640
mgamt 3 - 620
mgamt 4 - 620

(Quant consistently at 43/44 and verbal from 28-32)

Consistently, i have been scoring 600+ in mgmat for the last one month, now i took my gmatprep for the first time today. I took all above tests under strict timelines including breaks

I also wrote AWA and essay so as to mimic the official test in all above four tests.

Now comes the confusion , today i took gmatprep test and I scored 550 ( Q - 37, V - 27 ) , in case of Quant i have had 60% correct answers and in Verbal i had again 26 correct and 15 wrong answers in this test.

There is no possible way of analysing the gmatprep the way analysis is offered by mgmat in terms of difficulty wise Q / content wise etc.

in OG, I have an accuracy of 70 in SC ( under 1 min ) , 70% in CR ( under 2 mins ) and 45% in RC.

I have an accuracy of 75% in Quant of OG.

I have an accuracy of 70% in kaplan Q banks except RC.

Now, what do i infer ???????? am i ready for the gmat or not ??????? my target is 650 min

My gmat is scheduled on 17th Feb. , i am so confused and demotivated.