Yes, readings from home glucose meters can vary somewhat. But when the differences are that big I'm wondering if it's your technique that's the problem. There are so many different factors that can affect your result.
Are you washing your hands before you test? Are you drying them on a towel that's been out all day? Are you touching the bathroom light switch on the way out? Even the smallest bit of sugar on your finger can send your numbers up. What I do with my daughter is I swipe the finger with an alcohol swab right before testing to make sure the spot I'm taking blood from is 100% clean. If you decide to try this, make sure the alcohol has completely dried off the finger before you prick it.
But then also watch the hand you're taking the strip out of the vial with. Your best bet is to get your finger in the vial and fish the strip out by touching it in the middle and sliding it out. If you don't touch the ends, then you can be sure you didn't contaminate the strip.
Oh, and make sure you don't touch the strip with wet/damp hands. Moisture can cause an incorrect reading too.
Then after you prick the finger, wipe off the first little bit of blood that comes out to make sure you have a fresh sample. Sometimes I do this twice. I use a square of toilet paper for this. Then after you're done you can use the square to hold against your finger until it stops bleeding.
Do you smear the sample when putting it on the strip? You should try to touch the end of the strip to the droplet of blood, and try not to smear it against your finger.
How do you get the blood flowing? Do you squeeze the tip of your finger? Squeezing the tip of your finger to get the blood out will often give you higher than normal test results. But there are some other techniques you can try. Try lowering the hand towards the ground and put your other hand around your arm and act like you're pushing the blood in your arm down. The same technique works on the finger. I hold my daughter's finger at the base and squeeze gently from there and push up a little. As long as you're not squeezing so hard that it's putting pressure on the tip of the finger this shouldn't effect the result.
My daughter's a T1 diabetic, and I've been taking her blood sugar about 12x per day for over 2 years now.