Issues with NCV

I'm tearing my hair out trying to solve this one, hopefully someone can help.

I'm trying to set up a graph using NCV, which has worked great in the past, albeit only graphing one or two values. I'm trying to send 4 values and it's truncating the last one, i.e. the RRD file only shows 3.

My output is simply this:

Bus 1 IO/Sec: 0 Bus 1 Q-IOs: 46 Bus 2 IO/Sec: 0 Bus 2 Q-IOs: 47

My hobbitserver.cfg has a line to catch everything:

NCV_powermt="*:GAUGE"

I run the client side script, and this is what I get from the rrdtool dump

<!-- Round Robin Database Dump --><rrd> <version> 0003 </version> <step> 300 </step> <!-- Seconds --> <lastupdate> 1258672448 </lastupdate> <!-- 2009-11-19 18:14:08 EST -->

    <ds>
            <name> Bus1IOSec </name>
            <type> GAUGE </type>
            <minimal_heartbeat> 600 </minimal_heartbeat>
            <min> NaN </min>
            <max> NaN </max>

            <!-- PDP Status -->
            <last_ds> 0 </last_ds>
            <value> 0.0000000000e+00 </value>
            <unknown_sec> 238 </unknown_sec>
    </ds>

    <ds>
            <name> Bus1QIOs </name>
            <type> GAUGE </type>
            <minimal_heartbeat> 600 </minimal_heartbeat>
            <min> NaN </min>
            <max> NaN </max>

            <!-- PDP Status -->
            <last_ds> 46 </last_ds>
            <value> 1.0800000000e+03 </value>
            <unknown_sec> 238 </unknown_sec>
    </ds>

    <ds>
            <name> Bus2IOSec </name>
            <type> GAUGE </type>
            <minimal_heartbeat> 600 </minimal_heartbeat>
            <min> NaN </min>
            <max> NaN </max>

            <!-- PDP Status -->
            <last_ds> 0 </last_ds>
            <value> 0.0000000000e+00 </value>
            <unknown_sec> 238 </unknown_sec>
    </ds>

<!-- Round Robin Archives --> <rra> -----snip------

I can rearrange the output from the client script to say:

Bus 2 Q-IOs: 47 Bus 1 IO/Sec: 0 Bus 1 Q-IOs: 46 Bus 2 IO/Sec: 0

Then the dump from RRD just has Bus2QIOs, Bus1IOSec, and Bus1QIOs

So it's always dropping the 4th value.

Is there some sort of limitation or bug in NCV that only captures 3 NCVs?

Thanks!