Do you just want to update all your purchased items from standard to the most current "last" cost available? If that is the case, and you have been maintaining the current and last cost fields, you can simply do a "Multiple Process Selection" from your standard costing, processes menu.
Select the following fields:
Create cost master
Roll cost master
Cost buildup
Current to standard roll
Cost to update - current
Inventory cost to use - last
Purchased or mfg - purchased
Mfg method - all
This will update the cost of all your purchased parts from last year's current cost, to this year's last, most "current" cost. Then once you have done that, you can roll costs on all your mfg parts to incorporate the new purchase price into your standards.
If you are really switching all your inventory costs from standard cost to last cost, may I ask why? Also, this sounds like you have already gone through all the motions of calculating standard costs. So you have your BOM's and routers all in place? Do you have SFC installed and running? If so, I would appreciate speaking with you on some issues we are having.
We are in the implementation stages of SFC. We have BOM's and routers created. I have rolled costs and have a standard cost in place. We have not gone live yet.
Hope I was able to help. Let me know so I can dig for some more answers.