Honestly, the whole X raid days per week/ Y raid hours is overrated in the world of personal loot rng fiesta,titanforging, vantus runes and mythic+.
Let me explain. When char power growth was capped to heroic(and mythic drops) and you could masterloot, the big factor for guilds progressing was usually efficiency and adapting tactics. Now, there are the additional gearing factors outside of raids(like Mythic+ and titanforging), which none is going to account for. Its very impressive when a guild is top XX and raids Y times per week, its less so when the entire remaining time is spent grinding mythic+ in the first 2 weeks.
RNG personal loot fiesta is the difference between a shadowpriest and a warlock getting an ilvl 395 titanforge upgrade from heroic. One is a massive aid on the end boss on mythic and one is better disenchanted. There is no skill factor involved here, and its not like the guild with the shadowpriest getting the item raided less or more.
Last but not least, the Vantus Runes make a huge mark as well because it doesn't make a difference if u spend 2 extra reset days in week X without vantus and both guilds have vantus in week X+1. The guild with +2 raiding days just wasted their time.