This letter is/will be considered as my Authentication letter - which one correct

[Sureshvemuri]

I wrote (I wrote it Today.) a letter addresting to a Bank Manager and have given that to my Representative who will show this letter in the Bank when he deals with my Account.
In that I have written like this - "This letter will be considered as my Authentication letter" -
Here - can "will be " replaced with "is"?
I think, from today onwards this letter should be considered (in future) as a sort of Authentication from my side. So will be is more appropriate. Is my thinking correct?

Thanks,
Suresh

[Mister Micawber]

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I would have simply titled the letter: Authentication Letter. No need then to write anything to that effect in the body.
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Native English teacher at Mister Micawber's