Resolution: There is no batch timer in RV 7.x daemons; we batch on interrupt and will send however much data that the sender managed to get into the TCP stream before the daemon gets to complete the read from the application.
In RV 7.x, RV(R)D gets notified that there is data waiting for it from the application. If there is more than one RV message waiting, and if they will fit inside a single TRDP packet, then as many messages as possible will be put into the TRDP packet and sent. However, if only one message is there, RV(R)D will not bother "waiting" for another message to fill up the packet. So, the RV 7.x daemon will sometimes batch without waiting for enough messages to "fill it up".