Context: "I never imagined this letter accounts for the events of that evening."
The sentence is taken from a written testimony. The author states that she hadn't known a fact until she did an action (read the letter). Since the letter still exists and remains true to her statement (it still accounts for the events of that evening), the author used the present tense for the verb account.
In my opinion, the tenses of the sentence don't mix well. I'd rather use the present perfect for imagine, and then account in the present simple. What do you think, is her suggestion fine, or should the sentence be edited?