Difference in Classic and Constraint without detailed scheduling

Hi All.

We are using ECC ASCP plan and would like to test Classic, Constraint without detailed scheduling and Constraint with detailed scheduling.

I tried to set all of them and every time I see there is a huge difference in output.

1) Classic Plan - Planned orders are suggested on 15-June

2) Constraint without detailed scheduling  - Planned orders are suggested on 27-May

Is this a correct outcome that both the plan may have different planned order dates. Is there any document which can help to explore on these type and guidance to use the best one as per our requirement. We would like to work on a plan with daily bucketing.