How to calculate the calorie content of cooked food?
If you are concerned about the impact of whatever difference in calorie count cooked vs. raw makes, you are cutting it pretty fine. The margin for error is likely very small--probably smaller than your measuring errors, or the inaccuracy of your kitchen (or bathroom) scale.

Keeping an eye on calories is fine for weight loss. Reducing calorie intake and/or increasing calorie burning is the only proven way to do it. But looking out to avoid that 20 calorie margin of error suggests that either you're not cutting enough calories in the first place that 20 matters, or you're tormenting yourself over things you shouldn't be worried about. Cut yourself some slack, and don't sweat the small stuff. The simple act of realistically monitoring how much you eat is more likely to help you than obsessing over every single calorie.