Planned and Actual Dates Capture editable and reportable in RTC template - Is this feasible to implement?

I would really appreciate your help on the topic below, if possible for you.
I received the following request from the customer today and need to know if this is possible:

Environment: RTC 4.0.2
Solution Option 1 - Propose product change to make these dates editable and reportable. If this is not feasible, then

Solution Option 2 - Add custom fields in the task template for planned start /end and actual start/end dates fields and create reports/integration using these fields.
Business need is that from the project perspective, it is not always feasible for developers to update the task schedules on same day when task has been closed. In case the task is closed later, because of non editable dates, schedule completion related data is incorrectly recorded.

Questions are:

1) Is it feasible to implement one or the other option?
If so,
a) how?
b) can you point me to any specific documentation?

2) Is it recommended by Rational?
If not, which is the rationale of not recommending doing this?

Thanks in advance!