Don't bother waiting for an "official" MS response, you are unlikely in the extreme to get one.
"officially" there is only a very limited exception to the no transfer rule for OEM licenses. Normally the only exception is if your MOBO dies and you get it replaced on warranty. But as Summit noted, there have been a few recent replies where the users were able to convince MS Support to allow the transfer. But it is a rare exception.
Question: I've found a definition for SLP: System Locked Pre-installed.
I've found another reference that NSLP is Non System Locked Pre-installed. As I understand it, OEM NSLP is specific to a limited number of countries that have special consumer rights laws that do not allow SLP.
So from a action point of view, if you have an OEM NSLP license that you can activate on one machine you should be able to transfer it to another. But, you should check the license terms specific to that installation to see if you have the License Right to do a transfer.