how do you limit HISTFILE size in ksh?

[toney cassel]

I have recently changed my login shell to ksh. I have almost everything
worked out the way I want it, except this silly .history file. We're 
running HP-UX 7.0. The applicable section of my .kshrc file is as follows:

# Set history variables:
HISTFILE=$HOME/.history
HISTSIZE=30

Now why does my history file exceed 30 entries? My event number has 
incremented since the day I changed shells. It has not reset to 1 or
30 as I would expect it too.

Any help would be appreciatd - thank you!

G'Day,
Toney...