0.88 rise in 2 months is not a high velocity rise when the starting point is 6. The medics look at doubling time - a doubling time of 6 months is worrying and of 3 months or less is very worrying.
You can put all your PSA tests and dates into an online calculator which will work your doubling time out for you - assuming your previous test was done in August and was the 6.1 one, your current doubling time is 33 months / 2.7 years
But as others have said, it is sensible to discuss with the urologist.