Can anyone explain TokuDBs seemingly large amount of data_free for an append only table? I have a large table I've been maintaining replicating in parallel in innodb in one slave and tokudb in another.

I'm seeing promising results in expected compression ratios but am noticing something very strange about the data_free reported from information_schema.tables for the tokudb copy.

This is an append only table.  No updates or deletes.  I'll let the following table explain what I'm seeing

engine  data_length(GB) index_length(GB) data_free(MB)  Size on disk (GB)
InnoDB  728.40          195.63           61.00          939
TokuDB  453.42          119.07           27507.60       253


Can someone explain why the data_free is magnitudes larger than the innodb version.   Is data_free for tokudb expected to mean the same thing as it does for innodb?
I've seen tokutek guys explain elsewhere that table status figures such as data_length etc are basically rough estimates by the tokudb engine, and they are sometimes off by large amounts, so I wouldn't read too much into it.