Two offices quote the same figure for the same family petition, and the natural conclusion is that the market has settled on a price. It has not. A flat fee is a number attached to a described piece of work, and the description is doing almost all of the work, which is why one office's figure covers a case from intake through an approval notice while another's covers the preparation and mailing of a single packet. The number is the easy part to compare. The scope behind it is the part that takes an afternoon and a legal pad.
Separate the attorney's fee from the government's fee
The first line to draw is between what the office charges and what the government charges. U.S. Citizenship and Immigration Services is the agency responsible for setting and collecting filing fees on most benefit applications, and those fees go to the agency, not to the attorney, usually by check or online payment tied to the specific form. Biometrics, where a case requires fingerprints and a photograph at an application support center, may be bundled into the filing fee or billed separately depending on the form. A quote that says "all fees included" without naming the forms and the amounts is not telling you enough. Ask for the form numbers.
Once the form numbers are written down, the comparison gets easier fast, because two offices filing the identical set of forms are facing identical government costs, and any difference in the total is a difference in what the office is doing. If one quote is a thousand dollars lighter, find out whether it excludes the filing fees, excludes a form the other office plans to file concurrently, or excludes a stage of the case entirely. Sometimes the answer is that the cheaper office is genuinely leaner. Often the answer is that the case has been sliced thinner.
The five stages a flat fee may or may not reach
Most immigration matters move through recognizable stages, and a quote can stop at any one of them. There is preparation and filing, which nearly every quote includes. There is responding to a request for evidence, meaning a written notice from the agency asking for documents or explanation before it decides, which is common enough that it should never be treated as a surprise. There is interview attendance, where an attorney appears with you at a field office. There is a motion or an appeal if the case is denied. And there is the follow-on filing, the work that comes after an approval, which is a separate case with a separate fee almost everywhere.
A careful reader takes those five stages and asks, for each one, whether it is inside the quoted number or outside it, and if outside, what it would cost. An office that has done this work for years can answer in a minute, because the answer is already in its engagement letter. The answers vary honestly. Some offices include a request for evidence response because they would rather price the risk in than argue about it later. Others exclude it and charge hourly, which can be cheaper on a clean case. Either arrangement is workable once it is written down.
Questions that force the scope onto paper
Ask what happens if the case is denied, and specifically whether refiling is included, discounted, or billed fresh. Ask whether the fee covers one interview or every interview, since some cases draw a second. Ask who prepares the packet, who reviews it, and who signs the appearance form, because the attorney you meet is not always the attorney on the case. Ask what triggers an additional charge, in plain terms, with an example. Ask for the payment schedule and what portion is earned at signing. Then ask for all of it in the written agreement rather than in an email summary.
The moment to ask is before any money moves, and the tone can be entirely friendly, because a well-run office expects these questions and has answers ready. The engagement letter, sometimes called a fee agreement or retainer agreement, is the document that governs. If something was said out loud and matters to you, it belongs in that document, and a reasonable office will add a sentence. Read the termination clause too, the part that says what happens to unearned money if you leave or they withdraw.
Comparing the two quotes side by side
With the form numbers, the stage-by-stage inclusions, and the written agreement in hand, the two identical numbers stop being identical. One may cover a concurrent filing, a request for evidence response, and interview attendance. The other may cover preparation of a single form, with everything after it billed separately at rates you can now see. Neither is wrong. The one that fits depends on how complicated your facts are, how likely a request for evidence looks, and whether you want a predictable total or the chance of a lower one.
Write the comparison down on one page before you decide, because the details blur within a day or two and the page is what you will actually remember. Keep the engagement letter somewhere you can find it, along with the receipts for the government fees, which are separate records and often needed separately.