From looking at my scores especially on verbal. I realize it's impossible to get 49 or 50 if I had 3 wrongs in a row. I had 15 wrong on my MGMT exam and my score was 49. I got only a 48 when I had only 8 wrongs. The only difference between these 2 test other than have more wrong on my higher scoring test was that a had 3 wrongs in a row. The test I got 49 on the maximum number of wrong I had was 2 in a row. Same thing happened on my GMAT Prep Test. The first time I did it, I had 10 wrong and I scored 50. On Prep 2 I got 9 wrong and I scored a 48. The difference is that I had 3 in a row wrong again. I believe that it's okay for get the first few wrong and still get a pretty decent score.
For my test that were 49 and 50 I had 2 to 3 questions wrong within the 10 and yet my score was still pretty high. I think that as long as you don't get 3 wrongs in a row during the middle of the exam there should be no problem with getting 49+.
Notice the same thing in Verbal. Got first 4 right then the next 3 wrong, afterwards no more than 2 wrongs in a row. My score was 40.
My scores:
GMATPrep 1: Q:50 V:33 700
MGMT 1: Q:48 V:38 710
MGMT 2: Q:49 V33 670
MGMT 3: Q47 V:35 680
GMATPrep 2: 48 V:36 690
MGMT 4: Q48 V:40 720