Help with a thold template and CDEF

[meralias]

I'm trying to set up an interface utilization % threshold monitor, using the rrd_maximum instead of ifSpeed (for situations where ifSpeed would be incorrect, such as 10Gb interfaces) It wasn't working the way I was expecting, so I tried to set up a CDEF that would just return the rrd_maximum:

cdef=CURRENT_DATA_SOURCE,CURRENT_DATA_SOURCE,-,CURRENT_DS_MAXIMUM_VALUE,+

(You have to have at least one reference to CURRENT_DATA_SOURCE, so I take it, subtract it from itself, then add on the rrd_maximum)

On the interface I set up, the rrd_maximum should be 15000000, however thold is reporting 1224492.5061. Any thoughts?