XCRC/XMD5 small section of the file?

Some FTPd supports partial CRC/MD5 calculation if you input the start byte and the end byte
e.g. RaidenFTPd

[08:57:52] XCRC "17744.rar" 0 50000000
[08:57:53] 250 5A477C28
[08:57:59] XCRC "17744.rar" 0 100000000
[08:58:01] 250 6D4BCDF5

(First one is CRC between 0 to 50M, second one is 0 to 100M)

For some really large files, and/or multi-thread transfer, it would strain the FTP server's harddrive badly and will usually timeout the session (which is not really helpful).

Is it possible to add an option for this kind of "quick checking", checking the CRC / MD5 of the last 2MB (example) of the destination file, instead of XCRC the whole file?

I just had another file byte-shifted and it was too large for full file XCRC even with 200 seconds timeout, didn't realize it until 2 days after

I know not all FTPd support it but may be it could be add as an option (under FXP option)?