HBP's potions discoveries - why keep them secret?

[bibphile]

No: HPFGUIDX 140620

--- In HPforGrownups at yahoogroups.com, "bocadetomates" 
<kat.rohts at g...> wrote:
> So, finally I come out of the dark corner I've been lurking in to 
put 
> up a question that's haunted me for a few days now. I hope this 
> hasn't been brought up before: Has anybody ever wondered why the 
> discoveries a schoolboy (an exceptionally gifted one, granted, but 
> yet a schoolboy) made twenty years ago about better ways of making 
> well-known potions haven't found their way into the "official" 
potion-
> making guidelines (as Hermione calls them)? 
> 

I don't know why Snape didn't publish his discoveries but it's very 
possible that he has been teaching them.  As far as I remember Harry 
didn't use a potions book in his second through fifth years.  Snape 
wrote instructions on the board.  Snape could easily have been 
teaching his improved formulas.  Depending on how many students you 
think are in Harry's year it's possible that as many as 25% of the 
students in Harry's year got O's on their potions O.W.L.S. (more if 
some made O's but didn't take NEWT level courses).  If they were 
asked to make a potion from their own knowledge without instructions 
(and I have no idea if they were) then Snape's superior formulas 
might have contributed to the high number of O's.