I dont understand the question properly [assume you mean stops and not stints]
although reading though here should explain
http://igpmanager.com/play/?url=guide
1/ Your technical director will not be 100% accurate [although you have run the track twice+ before you should look at previous race results to find out how much fuel you used]
2/ if you worked out the above 10.769laps per stint, and the race is 53 laps long that leaves you 3 laps short, as detailed in the guide, so adjust your strategy to make allowances for these [by adding fuel to the first 3 stints to take them to 11 laps and leaving the last 2 as is]
"My
NB. You can also avoid over or under-fuelling by using a calculator. E.g. Spain is 66 laps, Tech director suggests a 4 stop [5stints] all with the same amount of fuel. 66/5 is 13.2 [or 4stints at 13laps and 1 stint at 14laps] meaning you won’t have enough fuel for your final stint, unless you have overfuelled the first 4.
3/ The easiest thing to do would have been to load last seasons setup [and looked at least seasons results] this would give you detailed information on how much fuel / tyres were used per lap [and then how much fuel was needed per stint] bypassing the "estimation" of your TD and giving you a more or less perfect fuel consumption
4/ + What Jamie says a high level TD will normlly underfuel you by a country mile, but this shouldnt matter as STEP 3 above should be the first thing you do before setting up for a race