When the labels say mixture Mag Oxide and Mag Citrate they typically are mostly Oxide. (it is cheap, that is why).

Is there a 1-800 number on the label? You can call them up and ask them the ratio. Here it is:
1-800-433-2990
I looked it up on their site and it does not give the ratio of each
http://www.naturesbounty.com/pages/products.aspx?PID=74
So you will need to know what you are taking, to know whether you can expect good results.

And I don't agree with Kathi.... I definitely think your daily use of a benzo, has you primed for reactive cramps, when the situation is "right". So your over use, may also combine with dehydration, or any other stressor on the muscles.
Even B6 deficiency will do it, since pyridoxal is involved with muscle functions.

You can look up the signs of benzo withdrawal, and cramping is one sign.
Your body gets used to things a certain way...and reacts accordingly. Benzos are eliminated more slowly in the elderly...remember when I explained the Dalmane issue for Alan in the past? That is why you changed the RX then.

You've had spasms/cramps for a long time. And you have posted many times that you cannot sleep. Both are signs of low magnesium.

And please don't take more than recommended. Stay within normal RDA amounts.