Noob question but how did you calculated the time without loads for the mod version? Did you had to do it manually or did you used some sort of script?

I use LiveSplit (http://livesplit.github.io/) with the SourceSplit (https://github.com/fatalis/SourceSplit/releases) component.

To enable for the MOD version, set your "Game Name" to "Black Mesa" in "Edit Splits", then make sure to hit Activate for auto splitting. Doesn't look like it works for the Steam version though :(... You might want to submit an issue (https://github.com/fatalis/SourceSplit/issues) to request game compatibility.