I've also had this happen and it's really frustrating and confusing. I once got a 3 (too low) but didn't feel hypoglycaemic so I tested again with a different finger and got a 17! I didn't feel like it was 17 either so I tested again on a different finger and got a 7! I didn't know whether to eat sugar (for the 3), take insulin (for the 17) or do nothing (for the 7). I ended up just settling with the 7 and leaving it at that. Thankfully, this happened to be a good course of action and nothing untoward happened! I actually got rid of my meter in the end as it was regularly giving me inconsistent readings and I totally lost faith in it. I got a meter from a different brand and the readings seem much more consistent.