ConversationIndex Corruption?

[Chad Podoski]

I have been doing some work organizing messages by conversation making
use of the ConversationIndex property. In most cases this works
great. However, when testing on old emails (also sent with outlook),
some emails I have come across are clearly in the same conversation
but all have different ConversationIndexes. What are the possible
reasons for this? Also, am I correct in my observation that the first
40 characters of the ConversationIndex specify the conversation while
each 10 character set after identifies a subsequent branches of the
conversation thread?

Thanks,
Chad Podoski