why is NOT using the ~ている form wrong in this instance?

Question

In a Japanese class, we were given a sentence to modify it into a conveying speech. So for example,

天気予報によると明日は雨が降る。ー＞　天気予報によると明日は雨が降るそうです。

Now, we were given this sentence.

田中さんによると鈴木さんは今銀行に勤める。

Our instructor emphasized that the correct way to modify this sentence into a conveying speech is to change the verb 勤める into a ~ている form such that

田中さんによると鈴木さんは今銀行に勤めているそうです。

But I cannot really see the difference with the above sentence, and the sentence below.

田中さんによると鈴木さんは今銀行に勤めるそうです。

Where the latter just uses the normal form of the verb. But here, the instructor explicitly said this usage is incorrect. Why?

Answer 1

勤めている means "to (currently) be employed at/by". Simply using 勤める would imply that 鈴木 will be employed at/by the bank in the future. But because the sentence uses 今, we must use the ～ている form.

If the 今 were omitted, then either would be fine, and the meaning would depend on the context, and what the context is trying to get say.

According to Tanaka, Suzuki (is currently/will be) (hearsay-ingly) employed by the bank.