this example is a modification of an OA (I've kept the structure but changed the words)
Today, because of progress in industrial technology, the same quantity of raw materials produces twice as many products as it did in 1990.
in the Manhattan SC book page 249 we have:
The first instance of the verb should usually match the helping verb in tense. If you change tenses, repeat the whole verb in the new tense.
Wrong: I have never seen an aardvark, but last year my father did.
Right: I have never seen an aardvark, but last year my father saw one.
So according to this rule the correct form of the sentence IS:
The same amount of acreage PRODUCES twice as many apples as it PRODUCED in 1910.
the book also stated:
In the rare cases in which the tenses do not need to match, the exact verb form missing after the helping verb should be present elsewhere in the sentence.
Wrong: Our cars were designed to inspire envy, and they ARE.
Right: Our cars were designed to inspire envy, and they do
I hope I could make my confusion clear enough
Many thanks in advance