It appears that this spell is only lasting roughly 6mins. This is not consistent with spell data from Lucy
http://lucy.allakhazam.com/spell.html?id=661 which shows 12.7 mins @L39 to 15.0 mins @L47. The date of that data is 2005 with the earliest spell info being 2002. But if you look at other pet haste spells such as
Intensify Death
http://lucy.allakhazam.com/spell.html?id=449 it shows a spell duration of 3.4 mins @L24 to 7.0 mins @L60 which is consistent with p99 and no change until 11/20/2007 when haste spell durations are updated.
Also the higher level spell Augmentation of Death
http://lucy.allakhazam.com/spell.html?id=1414 doesn't show a change from 17.5 mins until 11/20/2007
So I believe it is safe to assume that if the lower version and the higher version do not show a changes until 11/20/2007 then the middle version that 2005 data shows has a duration of 12.7 mins should probably last that long instead of the current 6 mins.