How do I properly use [sic] for a phrase? Or do I use it at all?

The actual sentence I am quoting is:

Company A will provide regular communications to Company B on the status of level of effort in comparison the projected monthly amounts contained in our contract.

Obviously there is a word missing. This is how I think that sentence should be quoted:

Company A will provide regular communications to Company B on the status of level of effort in comparison (to) [sic] the projected monthly amounts contained in our contract.

Is this even close? I am just not sure.

The term sic indicates "that an incorrect or unusual spelling, phrase, punctuation or meaning in the quote has been reproduced verbatim from the original". As you have not reproduced the quote verbatim – you interpolated (to) – it would be wrong to also add sic. See How do you quote a passage that has used '[sic]' mistakenly?, What can I do instead of [sic]?, and The usage of "sic" in writing for additional sic advice.

When you interpolate or modify material in a quote, enclose the addition or modification in square brackets, as in example below. See What is the proper use of [square brackets] in quotes? and How to add contextualizing text to a quotation? for discussion of brackets.

Company A will provide regular communications to Company B on the status of level of effort in comparison [to] the projected monthly amounts contained in our contract.

Only use [sic] when you don't change the original.

So copy the original, and place [sic] near the mistake:

Company A will provide regular communications to Company B on the status of level of effort in comparison the projected monthly amounts [sic] contained in our contract.

However, the preferred option (particularly when the error is slight) is to leave the [sic] on the shelf and quietly correct the quote, using square brackets:

Company A will provide regular communications to Company B on the status of level of effort in comparison [to] the projected monthly amounts contained in our contract.