B737 first officer reported receiving a revised weight and balance numbers well after departure.

Attributes
ACN	1541106
Time
Date	201805
Place
Locale Reference	ZZZ.ARTCC
State Reference	US
Aircraft 1
Make Model Name	B737-700
Operating Under FAR Part	Part 121
Flight Phase	Cruise
Flight Plan	IFR
Person 1
Function	First Officer Pilot Not Flying
Qualification	Flight Crew Instrument Flight Crew Multiengine Flight Crew Air Transport Pilot (ATP)
Experience	Flight Crew Last 90 Days 537
Events
Anomaly	Deviation - Procedural Weight And Balance Deviation - Procedural Published Material / Policy

Narrative:

After reaching our cruise altitude; we received an ACARS message from dispatch alerting us to a [weight and balance] error. Dispatch was sent the revision well after departure time; and the new data was then sent to us. We received it; and upon review; we discovered that the weight error was actually in our favor; and the only real change was a vr decrease of one knot. Flight continued uneventfully.while implemented to trap errors and provide accuracy to our performance; [our current method of weight and balance calculations] thus far have been mostly a headache. Late changes; denied passengers and putting crews liability in jeopardy all while causing a delay on at least 50% of my flights if there was anything I could do to help this situation; I would be glad to. It seems our hands are mostly tied.

Original NASA ASRS Text

Title: B737 First Officer reported receiving a revised weight and balance numbers well after departure.

Narrative: After reaching our cruise altitude; we received an ACARS message from Dispatch alerting us to a [weight and balance] error. Dispatch was sent the revision well after departure time; and the new data was then sent to us. We received it; and upon review; we discovered that the weight error was actually in our favor; and the only real change was a VR decrease of one knot. Flight continued uneventfully.While implemented to trap errors and provide accuracy to our performance; [our current method of weight and balance calculations] thus far have been mostly a headache. Late changes; denied Passengers and putting Crews liability in jeopardy all while causing a delay on at least 50% of my flights If there was anything I could do to help this situation; I would be glad to. It seems our hands are mostly tied.

Data retrieved from NASA's ASRS site and automatically converted to unabbreviated mixed upper/lowercase text. This report is for informational purposes with no guarantee of accuracy. See NASA's ASRS site for official report.