Question on NHL UNDER chase system

I saw a thread from expertcapper I think saying that they made some variations to the system saying after OT/SO you would bet on:

Over 5
Under 5.5
Over 6

Is there any reason that you would bet the OVER on the 5,6 line and UNDER on the 5.5?  I would think you would just blanket and chase the UNDER?

Why Over 5? I remember many games resulted Under 5 when the line is 5 last season..

PS: There will be long long losing streaks in this system. Be careful about it. Have a look at my UNDER System, hope you'll like it ;)

This is false this year. In fact, someone in the NHL forum was tracking picks by simply taking the over when the total was set at 5 and was hitting winners at more than 58%. Problem is the number of totals set at 5 shot down dramatically as the books adjusted.

There is a total tonight at 5 that has a huge chance of hitting