B1 visa for conference arriving 10 days early

Important caveat:

it has annotations about my company plus the month November 2017.

• the company is binding and if you change employers then you will need a new visa
• the month might be problematic but if it's multiple entry then it might work still in December. I never heard of a date annotation before, it's very odd because the US is such that the visa expiry date is the last date you can present yourself at the border asking for admission. You might need to talk to the embassy about this.

To answer the rest, the officer is probably going to work from the notes attached to 9 FAM 41.31 (or experience derived from there) so let's review that together.

The period of time projected for the visit must be consistent with the stated purpose of the trip. The applicant must establish with reasonable certainty that departure from the United States will take place upon completion of the temporary visit. Although “temporary” is not specifically defined by either statute or regulation, it generally signifies a limited period of stay.

and

The applicant must have specific and realistic plans for the entire period of the contemplated visit.

Most importantly:

An alien desiring to come to the United States for one principal, and one or more incidental purposes, should be classified in accordance with the principal purpose.

I am not an DOS employee and I do not even play one on television but to me it seems you should be perfectly fine.