If you're using a regulated mod where you can manually adjust the wattage then a small variation of the resistance isn't of any great importance. Most mesh strips tend to be low resistance and the stated resistance on the mesh strip packaging tends to be FAIRLY accurate, but it can vary. If you buy a pack of mesh strips rated at 0.13 ohms - and your mod informs you it is in fact 0.11 (or 0.15) don't worry as 0.02 Ohms difference isn't really a problem as you still get to choose the actual wattage you vape at - and you can adjust the wattage up or down to your preference. In addition, most mainstream Chinese mods aren't always that accurate at reading resistance - for example, I'm currently vaping on a Sherman 25 RDA with a 0.15 build - all my DNA mods read it at 0.15 so I'm confident 0.15 is accurate, if I put the same RDA on some of my budget Chinese mods the displayed resistance will be anything from 0.14 to 0.17 - this isn't a problem as if the board sends a little too much, or not enough, power to the coils because of the inaccurate reading I can always adjust the wattage to taste.
If you're getting wildly varying ohm readings then you have a problem (probably a loose screw clamping the coil or a loose 510 pin) but if the reading is only about 0.02 - 0,03 from what you were expecting and you constantly get the same reading then I wouldn't worry about it.
However, if you're using a mechanical mod - then it could be a BIG problem. but I wouldn't advise anyone to use mesh on a mech...