Here's the deal with any body fat composition unit (calipers, machine, electro-readers, homeo-static readers, water submersion) use them as a tool and that is it.
Everyone in the fitness world agrees getting dunked is the most accurate test for composition. Calipers are a measuring tool and trainers can use up to 99 different formulas to calculate a %. The electro readers (hand, feet, whatever) are the least accurate to be honest as too many factors interrupt the single frequency (water, food, fat, bone density etc...).
Nonetheless, when someone wants to use one of these devices as a tool I encourage them to use it as a simple too. What that means is, if you were to invest in some calipers, let's say, you would use them to measure the fat in a certain area on your body.
Let's say it is January, you start a HIIT cardio program coupled with 3 days of weight lifting for tone. You measure your stomach, tricep and thigh. You get X reading.
Now let's say it is March, you have been faithful to your plan and you remeasure the same spots and get Y results. What is more important is the difference between X and Y then the end computation.
The same is said for any "body fat" monitor. Be aware of the difference, not the number and always try to mimic the conditions of the first measure.