EOS wireless flash question

[Don]

When using 2 - 550ex with my 10d camera and flash both set in manual 
wireless, I get conflicting readings on my Sekonic Flash meter L-508. 
When I use just one 550ex and I pop the test button I get a reading on 
the flash meter say at f8. Also when I have both 550ex on and pop the 
test button the reading is say f8. Now when I push the shutter button 
and take the picture the reading on the flash meter is no longer the 
same. It will change from say f8 to f4. However when I only use one 
flash, the reading on the flash meter remains the same. It appears that 
in a wireless mode, the flash output changes somehow or the wireless 
frequency is interfering with the sekonic. Anyone have any ideas as to 
what is happening and is this normal.By the way, the exposure of the 
picture appears to be ok I am just wondering why thre flash meter 
readings change.

Don
*
****
*******
***********************************************************
*  For list instructions, including unsubscribe, see:
*    http://www.a1.nl/phomepag/markerink/eos_list.htm
***********************************************************