I have the same problems as described for Disk Sensei. In addition I found that the benchmark tool gives me an error message: Benchmark needs a Mac-formatted volume with 6 GB of free space. Please free up space on the drive and restart Disk Sensei. This with 400 GB free on my SSD. Also see two of the same drive as noted by SteveWhittaker.
I also upgraded to Trim Enabler 4, since I have a version 3 TE. Now TE manages to place two extensions in the Library, that I assume may have something to do with enabling Trim. Unlike DS, TE's button to enable trim does not give the message that the SSD about the drive not supporting trim.
After enabling TE 4, now DS 1.4 does give the comforting message: Trim is enabled.
Oskar, DS needs updating for High Sierra, please.