I don't really treat cmd+tab and cmd+` very differently, sorry. On my OS, both work: I can alt-` to cycle through windows of same application and alt+tab to cycle through each individual window (grouped by application); maybe that's given me the habit of treating alt+` merely as a filter on alt+tab.
Oh! This is perhaps also why I get annoyed by cmd+tab on Macs!!
Next tme on mac try cmd+' to cycle between windows of the same app(although im not sure, because it really is muscle memory). Cmd tab cycles through wndow groups? Or does it cycle through each window?
Which wm on which os do you use? gnome kde or something else?
Oh! This is perhaps also why I get annoyed by cmd+tab on Macs!!