Favoured maps all dropping at low tiers

Have selected cemetery and city square with my 4 favoured map slots available, expecting a greater proportion of the T16 map drops would be these maps. But so far all of the cemetery maps (x14) have dropped as T11 and city square (x13) T14. Assume this is related to the maps themselves being lower tier on the atlas, so if this is the case am wondering how drops work for maps that are lower tier on the atlas? Considering cemetery is T6 but dropping T11's and city square is dropping T14 (in line with atlas).
If this is the case how do people actually get lots of T16 drops for maps that are low tiers on the atlas such as cemetery?

It depends on your voidstones. If you have all 4 and all 4 are active, every map can potentially drop as t16. But, they can also drop lower.

For example, I run 4 watchstones with most favors set to crimson temple (slowing pushing for mage blood). I get mostly t16s, and more often than not its the desired map. But I still get other t16s in a reduced capacity and lower tier maps beyond that as well.

A map can only drop as high as its highest tier, so if your map is on the atlas as a tier 8, don't expect to see one drop higher. However, not all maps that drop in t16 are t16. No matter how high your chance to drop a tier higher, a map drop might roll as an 8 and get "upgraded" to 9.

I'm also pretty sure that the old mechanics still apply, which means the highest most monsters can drop are +1 above the map being run and map bosses having the only potential +2. So what that means is the highest you can get out of a tier 10 would be a potential tier 12 from the boss and anything else would drop as 11 or lower. There are a few exceptions to this like strongboxes, but thats the jist.