Backfilling raised beds... sand in "soil mixes"?

I was about to purchase a few cubic yds. of the "#1 soil mix with mushroom compost" from one of the largest landscaping material outlets in our area, but I'm curious about one of the stated ingredients. The mix includes "a small amount of sand," which worries me... My native soil is virtually solid clay - I've tilled, and have built about a 12" retaining wall & need to backfill (and mix/till again) with a "good" soil & of course, lots of compost/org. matter. I know we've discussed the dangers of adding sand (especially in smaller amounts) to clay soil, so what gives with these retail/wholesale soil mixes including it? FYI, I checked out several other distributors and they all include sand in their soil mixes as well... Do I need to stay away from this stuff? Thanks!

Heck no. Sand is good if it is mixed with compost. I use what ever I can get my hands on with my clay. Clay and sand only = concrete not mixed with compost. Use it.

Whew! Great - I was starting to worry that I wouldn't be able to find anything that would work! I'm excited to work with mushroom compost - have never used it before.

That is the most common source of manure and sawdust used a lot in horse housing. Mushroom compost is what I use most of the time building soil because I can get it free. You will love the soil it creates.

Sometimes I wish I lived a little ways outside the city, so I'd actually have a steady source of compost/soil ingredients! The soil is being delivered tomorrow morning - can't wait!