Summary, Two (and presumably more) VentMon at One LAN Display on http://ventmon.coslabs.com/breath_plot incompatibly
In my residence I configured two VentMon for my LAN.
When each are connected ONE AT A TIME they report resperation to the breath plot correctly.
Normal, single VentMon opperation / Display

Example of breaths when only one VentMon connected.
Conflicted Unintelligible display
However when two are connected the breath plot is in error.

Example of breaths when two VentMon connected and apparently sending to the same breath plot.
Test condition
Two VentMons at LAN address 192.168.1.223 and 192.168.1.225