@mmasnick iirc, “adjustments” indicate your insurance was able to negotiate the total down from the sticker price. They should be the difference between the full amount of the bill your provider was hoping to get and the amount they are able to bill for, that amount your insurance company is paying + your contribution.
E.g. $5k gross total: if per the agreements between the insurance company and provider they pay $3500 and you pay $500, then that means $1k is “adjusted” away.