On the '85 Clarkson you'll see in his PH for hist best season, I had him throw 17 consecutive starts without him dropping below 100. I had used him very conservatively in he first half of the season and got these starts around game 135-145 range. I've also gotten between 7-9 consecutive starts at 100 from King and Ramsey by employing the same conservative first half use and aggressive second half use.
Similarly, I've stashed guys in AAA, such as Wiley Piatt in league 10175 (I'd post his game log but my phone won't let me). He threw 8 consecutive games at 100 and used up virtually all of his available innings in doing so between games 110-120.
So, I think there is a consecutive game penalty, but I think it only applies if a pitcher is already past X% of his team's games AND is projecting to be over Y%. I think X is 50% or thereabouts and Y is somewhere between 52-73%.
But I'm not certain and I have all of my fatigue notes on my home computer...