bigboy, they are not cautions. They are just instructions for taking your Spring Forest Qigong practice from good to best.
The idea is that after doing SFQ, you can gain additional benefit by not interrupting the energy patterns you've established. Hence the suggestions to abstain from the more disruptive activities for a while after you have done your practice.
The recommendation is for the sitting and active exercises.
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I like the sitting exercises in the morning, namely quiet time, too. How ever Master Lin has suggested that the optimum time for the active exercise is the 5 - 7 am / pm times. And the best for the sitting is 11 - 1 am / pm. This doesn't mean the that doing the other ones is bad. Since the "Do what you can when you can" would seem to be higher the list of guidelines for Good - Better - Best practices.
You are perfection.
Iam2 