GMs do not necessarily have any sort of information that's not available to the average user who reads stuff and participates actively in forum discussions. Most of our GMs fit that description, so they'll generally provide good advice.
In this particular case, in slow-paced tactics your players make more passes before they get to a shot that they deem good enough to take, therefore they have more chances to turn the ball over. On the other hand, after someof the recent GE chances, your players have been made a little bit more likely to carelessly throw the ball away. I don't have any clear-cut evidence about which is likely to produce more turnovers on average, but then again, I've never looked at the issue in detail.
"I don't know half of you half as well as I should like; and I like less than half of you half as well as you deserve."