Is "mg" being used correctly?

I saw a chart saying
"Here are my rough estimates:

5mg is threshold dose
10mg is a mild buzz
20mg-30mg is a mild stoner
40mg-50mg is a very strong stoner
60mg+ is only for those with a high tolerance; otherwise your ass is horizontal.
"

Ohkay. Seems like a pretty legit chart considering I saw an ad for cookies with "38mg" each.

Here is where I think that people are using "mg" improperly.

If I make a batch of cannabutter with 9g of primo bud and 8oz clarified butter I will yield 1/2# of cannabutter at 1.125g of THC/ ounce.

If my cookie recipe calls for 1/2# [1 cup/8 ounces] of butter and yields 20 cookies that means that each cookie will contain roughly .45g of THC.
There are 1000 mg in 1 g
Thus,
.45g x 1000 = 450mg

That is WAAAAAAY more than any dose I have seen on other medibles. Am I making Killer Cookies? [figuratively speaking, I know you can’t die from pot :p ]

Or do people really mean centigrams [cg] when they are measuring?

There are 100 cenitgrams [cg] per gram [g].

Thus,
.45g x 100 = 45cg

Which seems to match the chart above [plus all of the doses on packages] better.

Can anyone help me out with this conundrum?
Does anyone know what’s up? Am I overthinking this?

I feel it is important for me to know the proper dose before I make butter to reduce the chances of wasting my precious green.

What can I say? It’s the asian in me.

>.<