VDOM links and NPU offload

According to hardware acceleration handbook, traffic that goes over inter-VDOM links can be offloaded to network processors via a special kind of VDOM link. I have a Fortigate 200B (includes NP2) in one location, and a Fortigate 200D (includes NP4lite) in another, and neither shows this special VDOM link as being available. Looking at session list, none of the sessions that tranverse the VDOM links have the "npu info" status, which, I assume, means that they are not offloaded. Sessions within a VDOM that meet fast path requirements (and in case of 200B, enter and exit through NP2-connected ports) do get offloaded.

 

The handbook has the following statements:

 

"FortiGate units with NP4 processors include inter-VDOM links that can be used to accelerate inter-VDOM link traffic"   And   "Some FortiGate units include NP4Lite processors. These network processors have the same functionality and limitations as  NP4 processors but with about half the performance"   As well as   "FortiGate units with NP4 processors include inter-VDOM links that can be used to accelerate inter-VDOM link traffic."   Is that last part not applicable to NP4Lite processors, or do I have a potential configuration issue that prevents me from seeing and using the npu-vlink interfaces? I don't have access to any boxes with the "big boy" NPUs to compare, and while we're considering an upgrade to a pair of 300Ds, which include a full-featured NP6, I want to clear out all potential questions before we part with five figures - the way the handbook is worded, it can be understood that the accelerated VDOM links are a feature of the boxes with two NPUs, i.e. 900D and up.