strike zone

[ToGreySt]

When I was getting patched to work high school ball, my trainers had me work on a pitching machine and taped my work. Their initial reaction about me was my zone was too small, they took me aside and said that I can give them an extra ball's width on the inside and two on the outside, both of those conform to what they called the "high school" strike. my question is this, if your zone gets widened for high school and lower levels (mine sure does), at what level do you use the strict interpretation of the zone? do you wait till college ball? or high school playoffs?

Joe