Hi kjbusa and welcome.

Yes, you can lose weight on 18/6, eating under your TDEE, but you could lose more weight if you could move your eating window sooner.

I’ve posted here (first post) 3 studies about this subject:
https://thefastdiet.co.uk/forums/topic/daily-20-23-hours-fasting-window/

Copy-paste:

I’ve also read that when-the-eating-hours-are is important for weight loss. If you have your eating window in the daytime you are losing more weight than having it in the evening. And the cause is that insulin release is greater in the evening, at identical meals.

This study I think it says it all: the study compared the effect of eating a large breakfast versus a large dinner: both groups ate 1.400 calories, BF group lose 8.7 kg, D group lose 3.6 kg. So yes, the time of your eating window is essential for weight loss.

“So what this study did was to randomly assign two groups of overweight women to eating a large breakfast (BF group) or a large dinner (D group). Both ate 1400 calories/day, and the macronutrient composition of each diet was matched – only the timing of the largest meal was changed. While both groups lost weight, the BF group was clearly superior for both weight loss and waist size (important measure of visceral fat) by almost 2.5 times (-8.7 kg vs -3.6 kg).”

Extras from Dr. Fung’s article: Circadian Rhythms – Fasting
https://intensivedietarymanagement.com/circadian-rhytms-fasting-17/

And here is the link for the whole study: High caloric intake at breakfast vs. dinner differentially influences weight loss of overweight and obese women.
http://onlinelibrary.wiley.com/doi/10.1002/oby.20460/epdf

Another 2 studies I found in this article in The Washington Post: Why eating late at night may be particularly bad for you and your diet.
https://www.washingtonpost.com/national/health-science/why-eating-late-at-night-may-be-particularly-bad-for-you-and-your-diet/2015/08/24/ad8b85ac-2583-11e5-b77f-eb13a215f593_story.html

Extras:
“Two recent studies have shed new light on the potential impact of timing. In a study of 420 overweight or obese people published in 2013, those who ate their major meal after 3 p.m. lost less weight during a 20-week weight-loss program than those who ate that main meal before 3 p.m. — even when the amount they ate, slept and exercised was the same.

“This is the first study to show that eating later in the day . . . makes people lose less weight, and lose it slower,” even when the amount people ate, slept and exercised was the same, says the study’s lead author, Marta Garaulet, a professor of physiology at the University of Murcia in Spain. “It shows that eating late impairs the success of weight-loss therapy.” In the 2013 study, the early eaters lost 22 pounds, the late eaters only 17.

In a subsequent small study of healthy women published this year, Garaulet and her team showed that when participants ate lunch after 4:30 p.m., they burned fewer calories while resting and digesting their food than they did when they ate at 1 p.m. — even though the calories consumed and level of activity was the same.

What’s more, when the participants ate late, they couldn’t metabolize, or burn off, carbohydrates as well as when they ate earlier. They also had decreased glucose tolerance, which can lead to diabetes. (The two-week study did not track whether the women gained or lost weight.)”

Direct links to the studies:
1. Timing of food intake predicts weight loss effectiveness.
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3756673/

2. Meal timing affects glucose tolerance, substrate oxidation and circadian-related variables: A randomized, crossover trial.
http://www.ncbi.nlm.nih.gov/pubmed/25311083

Good luck!