Unbalanced bandwidth reported in extra-info

When I scan the extra-info data from July for routers that reported more bandwidth read than written in a given 15 minute interval I find quite a few examples. Here's one:

write-history 2010-07-30 05:23:10 (900 s) 631808,48128,28672,1436672,1487872,1076224,860160,1084416,1443840,1492992,334848,1538048,1835008,1281024,21504,2844672,1456128,1641472,21504,1600512,2584576,1123328,24576,1881088,1755136,1750016,26624,1568768,1318912,753664,1013760,991232,15360,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,1824768,1720320,1221632,25600,1684480,1898496,363520,916480,1755136,842752,14336,0,0,11264,0,0,0,0,0,0,0,0,1847296,2082816,1767424,23552,664576,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,1115136

read-history 2010-07-30 05:23:10 (900 s) 1223680,41984,24576,4365312,4619264,3951616,2774016,4028416,6646784,7943168,1826816,8904704,10902528,6670336,18432,14535680,8086528,7943168,19456,6751232,14049280,6567936,21504,9063424,10653696,10608640,23552,7103488,5774336,3519488,5557248,5390336,11264,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,5951488,10020864,7044096,447488,9719808,10972160,331776,4963328,9638912,4784128,11264,0,0,12288,0,0,0,0,0,0,0,0,5955584,11724800,10200064,25600,1619968,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,3531776

Note:

1847296,2082816,1767424,23552,664576

written against 5955584,11724800,10200064,25600,1619968

read. That's probably not just directory fetches. My guess it's client bandwidth. There may even be cases where it's hidden service bandwidth - if the service is running 'locally'.

I ran a scan against the 30th July to pull the routers this happens to. I only pulled the guys that reported a 4MB plus difference for any given 15m interval. The same guys show up again and again, so they are doing something different to everyone else.