Twice as much/many again

[Little man]

Hello.
Could you, please, explain the meaning of these expressions - twice as much again; twice as many again. Some examples:

1. Old fashioned steel armor weighs twice as much again.2. The output of the average worker today is twice what it was 50 years ago and will be twice as much again in 50 years time.3. By the middle of the nineteenth century there were twice as many; by the early twentieth century twice as many again.

I think, because "half as much again" = 150, and "twice as much/many"= 200, that "twice as much/many again" means 300. I'm I right?

 

[Tdol]

Where are you getting your numbers from?

1. Old fashioned steel armor weighs twice as much again.
If modern armor weighs, for example, 2o kilos, then the old fashioned armor weighed 40.

2. The output of the average worker today is twice what it was 50 years ago and will be twice as much again in 50 years time.

The output today is 200% compared to 50 years ago. It will double again, making it 400% when compared to the starting point, or 200% compared to today.

 

[SoothingDave]

Twice as much "again" I have never read before. But I would understand it to mean what "half again" means. If new armor weighs 20, then the old weighs 60. (2 * 20 = 40 plus the original 20 = 60)

 

[Little man]

Thanks for your replies. I agree that it is strange sentences, but I found it in a dictionary.
These examples are listed in Oxford living dictionary, under the item 1.2 in the entry of the word "again".
Another example from there:
For every £1 received from members' subscriptions, we have to raise more than twice as much again to fund our charitable activities.