It Depends!
This does not make any sense at all and I think you have misunderstood the information given by your attorney completely and you should check back with him for clarification.
First of all, you cannot be made to plead guilty twice for the same crime and there is no ands, ifs, or buts about it, so you will either plead guilty to a charge of Petit Larceny or to Disorderly Conduct, and that is it. There is no going back to court a second time on the same charge.
Also, whether you do10 days of community service or 100 days, and are ordered to pay a fine of $10,000 instead of $200, the criminal charge against you will not be dropped; it is a legally and procedurally not possible. It is possible however to have the record expunged but that cannot happen either until completion of the probation period which you are going to be placed on by the court, and the period of probation for a Class A misdemeanor in New York happens to be 3 years long.
As to how this will affect your immigration status; well, a non U.S. citizen alien who is convicted of a crime is said to be "Removable" from the United States. Such an alien will more likely than not be arrested by I.C.E. agents and placed in detention where "Removal Proceedings" against him will commence. But an alien with no drug-related convictions and whose misdemeanor conviction(s) do not amount to an "Aggravated Felony" under immigration law, is by statute eligible for an Immigration Bond and can apply to the immigration court for Cancellation of Removal.
I am sorry, but you asked and it is important that you know what will be coming down the pike so at least you can plan ahead for it and be prepared. You really need to talk to an Immigration attorney more than a criminal defense attorney as soon as possible
fredrikklaw