For my CMDR those infos in the EDSM dashboard are also not correct, like in my trip (stats and more here: Elite forum) I came across 28 ELWs (most first discoveries), but EDSM only counts a total of 14 first and 19 total visited.
That's one reason why I have EDD running in parallel on a second screen while playing.

White dwarfs, neutron stars etc. are basically towards the very upper and low edges of the galaxy, like the last systems you can visit out there, sparsely mixed with other rarities and main sequence stars. As I didn't have a AFMU in my ship, I did not use any neutron or such boosts, only some synthesis to get to some remote systems to tick off an item in the Codex. And those were usually white dwarfs.