Hi Sugan,
If the help is not enough, I recommend to make an individual test in your sandbox to understand what is the meaning of each parameter.
For example, you ask about the meaning of Last lot exact. This is what the help says:
Controls whether the last lot is planned exactly in the whole plannning
horizon, and not according to the settings for the lot-sizing procedure or for
the rounding value/rounding profile.
When you select this field, the quantity available is zero at the end of the
net requirements segment and the gross requirements planning segment in the MRP
list and the stock/requirements list.
This means that you only procure what is needed. This avoids remaining stocks
and, when applicable, high scrapping costs, but the remaining requirements are
covered by the last lot. This is useful for discontinued materials.
So this what you can do if you want to understand the help. Imagine that you have a code with minimum lot size and rounding equal to 500 CS.
This is the MRP result using lot size MB:
As you can see at the end of the product life (once there is no more demand, you will see that you have a remaining quantity.. cause because you had monthly lot size and rounding qty = 500 CS.
Imagine that you copy lot size MB in a new lot size Z2, but you flag the parameter: "Last lot exact". So the only difference between MB and Z2 will be the Last lot exact flag. You run the MRP and this is the result using Z2:
Note that there is no remaining qty. So as is mentioned in the help, this helps to avoid remaining quantities at the end of the product life.
You can follow the same approach to understand each of the other fields if the help is not enough.
Thanks and Regards,
Mariano