Here you will always be able to see progress on the upcoming four chapters of the current volume - if there's less than four planned chapters left in a volume, then the progress bars will only run until the final chapter of the volume. The reason it's not all chapters of the current volume all the time is because my chapter plans don't always go to... well, plan. It's happened on several occasions that I've had to slot in an additional chapter because I couldn't fit all that I wanted in one (since I'm trying to keep chapters within the same length span of 2000-4000 words). This, plus me having an entire folder of drafts of scenes for future chapters, is why the progress bars can get weird sometimes and there's a nonzero chance that there'll be times when later chapters have more progress than earlier ones.
All gray fruits means I haven't even started writing the chapter. One coloured means I've at least started it, but is less than halfway done. Two means I believe I'm past the halfway point. Three means I feel it's close to being done. Four means the writing's all finished and it's in the proofreading/editing phase. Five means it's all done and ready to publish!
What will promise you all is the following: If a chapter is ready to publish, and the following chapter has at least reached the proofreading stage, then a chapter will be published the next Friday. The progress bars themselves will be updated at the very least once a week, usually on Friday or Saturday, and can update more frequently if I feel it's called for.