I’ll disagree with other input that this isn’t a big deal. I believe it is.
According to Fung, it takes about 12 hours to enter fasted state / ketosis. At that point your metabolism has switched to primarily burning body fat for energy. (It’s not exactly binary, and the longer the fast the deeper the ketosis, up to about 7 DAYS where the depth of ketosis is pretty flat. But in the early hours the depth is increasing very fast.)
So there is a difference between “fasting hours” (16 in 16/8) and fasted state hours (4 in 16/8). 17/7 is adding 25% to your fasted state hours. And the 5th hour is deeper ketosis than the first 4. So quite a bit more than that in effectiveness.
So yes, 17/7 is better than 16/8. And it’s half way to 18/6, which is even better. It doesn’t take long before the number of eating hours is so short that you are basically just eating once a day, which is OMAD. I’ve been doing that for 3½ years. Lost my weight and liked living and eating that way. it’s just normal. No desire to go back to frequency eating.
So by all means listen to your instincts. Reduce your eating window as you feel comfortable doing so. Skip lunch occasionally and see how you feel. Many people find, once they get used to 16/8, that going to one meal (usually dinner) is pretty easy. IF is a very healthy lifestyle leading to reduction in body weight, enhancement of the immune system, improved nutrition, and many other benefits.
I wouldn’t be obsessed with the numbers to be honest. It would be better to stick with 16eight then to try to go longer and consistently fail. Having said that, try it! You’ll know if it works for you or not.