You should have posted this in the LFSLapper section.
However, as you probably can't move it....
...the earliest copy of lapper that I've still got backup of is version 5.714.
I've attached copy.
Will this work with your version of LFS?
If so, have a look at this post HERE, which is a copy of a drift meter I wrote for lapper v5.714.
The post includes an amended LFSLapper.lpr configuration file with necessary coding included, and is in zip form, which you can download, unzip and copy over original file.