Storing Stats as Variables and the Applying the Variables after Class Change

Okay well my title is pretty specific to what I need but I am need of a step by step on how this is done.  I am currently trying to do this and have successfully stored the variables as I can check by hitting F9, but after I try to apply them my characters stats are still the same, or at the very least are showing the are the same on the status screen.  How would you go about storing and applying variables yourself?

EDIT:

Okay nevermind figured it out I was using Change HP instead of Change Parameters.  However my attack is increasing by the total attack and not the base value, how do you store base attack and defense rather than the equipped attack and defense number?

EDIT 2:

Found this formula from a previous answer that Mr. Bubble gave.

var = $game_actors[1].param_base(2)

Does anyone see an issue with this formula for my use?  My test run seems to be working, but I haven't used it across the board yet for all stats.

The link to that post was:

http://forums.rpgmakerweb.com/index.php?/topic/12393-variables-for-parameters-use-base-stats-or-total-stats/

Hope this helps anyone with the same issue.