Accuracy of Chapman's OT times?

Hi,
I'm hoping do the OT in the next couple of months and am considering the time that will be required to complete the track with the side trips I'd like to do. Obviously the weather will play a big part in determining the time taken and the side trips that are possible, but I was wondering how accurate the times in John Chapman's Overland Track book are in general? When we were down in Tassie in November we did a number of day walks in addition to a three day walk into the Walls. We found the time estimates in Chapman's Days Walks Tasmania to book be pretty conservative (we're reasonably fit). Is that the case with the OT book as well?
Thanks!
Cheers,
JB
I'm hoping do the OT in the next couple of months and am considering the time that will be required to complete the track with the side trips I'd like to do. Obviously the weather will play a big part in determining the time taken and the side trips that are possible, but I was wondering how accurate the times in John Chapman's Overland Track book are in general? When we were down in Tassie in November we did a number of day walks in addition to a three day walk into the Walls. We found the time estimates in Chapman's Days Walks Tasmania to book be pretty conservative (we're reasonably fit). Is that the case with the OT book as well?
Thanks!
Cheers,
JB