Crockpot Fantasies/Failures, etc. 4

It's very late, and I shouldn't be blogging, but I am kicking off what will hopefully be a month of good eating habits tomorrow, and so I need to stuff myself with everything yummy in the house tonight! I've got food cooking in the oven while I type--eight minutes left! Yesterday I had high hopes for this recipe:

Steak with Mushrooms and Onions

2-2 1/2 lb. boneless beef bottom round steaks (or braising steaks), fat-trimmed, cut into 6 equal pieces
1/2 cup steakhouse sauce
1 T vegetable oil
4 cups sliced mushrooms
1 medium onion chopped
1/4 t salt
1/2 t ground pepper

1. In Ziploc bag, combine steak and sauce. Seal and refrigerate at least one hour, up to 8.
2. Remove stakes from marinade.
3. Heat oil over medium high heat. Add steaks and brown, turning once, 2 minutes per side.
4. Layer mushrooms, onions, and browned steaks in slowcooker. Deglaze skillet with a small amount of water and add pan juices to cooker. Sprinkle with salt and pepper.
5. Cover. Cook on low 6 to 8 hours or on high 4 to 6 hours, until meat is tender and cooked through.

Because I lured Lorena away from her cooking duties by loaning her North and South, I offered to share some of this with them, knowing we would not eat it all (only 1/6 of us really appreciates beef). They were excellent food critics, and agreed with me that the meat was not very tender, although the flavor was good. Dan really liked it just the way it was and didn't think anything was wrong with it. We didn't all eat dinner together because everyone was every which way that night, so none of the kids tried it. I would like to try it again, because I think the recipe had thicker steaks in mind--it says to divide the meat up into six pieces and mine came already cut up into 8 pieces. Any experts on bottom round beef out there? Maybe it's always that way. If anyone tries out this recipe, let me know it turns out.