Looks like LplAMSenderP.nc line 15 writes over the wakeup-interval that I set prior to calling AMSend (e.g. LowPowerListening.setRemoteWakeupInterval( pkt, 2048 ) setting it to 0 (the default from SystemLowPowerListening.getDefaultRemoteWakeupInterval) prior to it getting to DefaultLplP.nc.
This results in the message only being sent once (assumes it is ONE_MESSAGE in DefaultLplP).
I encountered this while using CTP and realizing that CTP-MaxRetries was determining retransmissions instead of LPL as I would have expected.
Sorry if I am not using this correctly - but seems like a bug.