Material ledger production start up

Question

Dear expert,
we are working on a project that has two main objectives:
1) now the customer is using the mtv 103/105 and we want to move to the 101
2) now the customer is using a custom 'medium price calculation' and we have to activate the material ledger.
I red the note 596558 and I have some question; first at all I would like to find some documentation about this activity and the effects of  a Material ledger production startup, could someone tell me we can I find info ?
The question are
At point f) is wrote
u201CYou should always transfer purchase orders and purchase order histories before activating the material ledger. This ensures that the system translates the purchase order history in all additional currencies.u201D
What does it means? Why it is necessary translate? How?
If a company has only the local currency is it necessary the translation?
At point j) is wrote
u201CWe recommend that you close open orders before activating the material ledger and recreate them after the activation if required.u201D
WHY?
The posting logic for postings that reference a purchase order is changed in the parallel currencies due to the activation of the material ledger. As a result, there may be unexpected price postings and exchange rate difference postings for purchase orders that are not closed in business transactions (goods movements and invoices) that are posted later.
Which unexpected postings? Refers to new u2018Transactionu2019 (e.g. BSX, WRX, PRD, KDM, u2026) used after the material ledger start up? 
Now the customer is using a custom u2018medium price calculationu2019; we think to reverse all movements in the year (103, 105, invoices) for order item not closed and recreate the goods movement with  the new model (101, invoices) after the ML activation.
Thanks in advance.

Answer 1

In our case CKMSTART was definately done before Inventory load. This Tcode was part of config prior to Master data creation and migrated data loads....