I presume you have calculated these delays using the average delay times in the IRI time table ( As the scheduled reversal time in each of these places is only 10 minutes according to the TT). Such a calculation ( if you have done so) is very inaccurate. I've regularly seen trains arriving on time or with minimal delay even if the average delay in IRI is mentioned as 1:00 or more.
Even if there are delays in reversals at these stations, it is because all three stations lie on single track routes. VKB-PRLI-PBN-AWB is a single track. Even if the loco reversal is done in 5 minutes, if the line is blocked, then the train will...
more... always be delayed. That is one reason why this train also has a lot of slack ( more than required, in fact) time.