I would suggest that possibly you are under developing the prints, grey whites and blacks would lead me so belive this is the case.(posted 9319 days ago)I would only change one facet of your procedure at a time, then you can tell if that change has had an effect.
Try making five identical prints and developing them at different times, 30 seconds, 1 minute, 1 minute and 30 seconds, 2 minutes and 3 minutes. See what the difference is , I think you will find that the longer the development the darker the blacks and the better the contrast.
If this helps but doesn't completely solve the problem, try a different set of exposure times, in conjunction with the different development times. Keep notes, write right on the back of the prints with an indelible marker, before you get them wet, with what you did, so you can make changes and not repeat the same mistakes. Don't worry about ruining these prints, they are tests not finished prints.