Advise on more cardio?

[babylu22]

I have been told by fitness instructor to do (in a 5 day span)

1- 40 min. cardio
2- aerobics class (total body)
3- 40 min cardio
4 20 min cardio / 5 excersices for upper body (2 sets of 10)
5 20 min cardio / 5 excersices for lower body (2 sets of 10)

Every day also includes stretching and a sit-up workout made by the fitness instructor (except for aerobics day)

I asked aerobics instructor about 1-2 days a week to "step it up" and do some extra cardio but she said that this work out plan is all I need as long as I work out hard (which I always do).
I want to lose a few pounds and tone up and I have always heard that if you reach a plateau that you need to do some more things.

Which is true, stay with the plan I have been given or do some extra cardio a couple of days a week?

Any advice would be great!

[Boss Man]

Stick with the plan. If you plateau, it might well be a diet issue, more than the Cardio becoming ineffective. THe plan is obviously geared to keeping your Cardiovascular system guessing, hence why it's not the same kind or duration of Cardio every day.