4 questions before you choose the route.
This page identifies the right question and evidence. It does not determine the legal outcome on a reader’s facts.
What is the stack of documents?
MSA, PO, PI, quality protocol, vendor T&Cs, WeChat deltas.
StackWhich text claims to prevail?
Read both language versions of the order of precedence.
PrecedenceWas the PO an offer or a confirmation?
Who sent the last paper before shipment started.
Last shotDid performance accept the other terms?
Shipping after a conflicting confirmation is often treated as assent.
ConductWorking rule: Parties often sign a framework (MSA) and then issue POs, PI, vendor confirmations and WeChat quantity changes.
The signal ledger.
These facts move the question beyond a label and into a product, money-flow and control analysis.
Bring a compact evidence docket—not a pitch deck.
Give a compliance team or counsel the operating facts that reveal the perimeter.
Questions people ask before they build.
Short answers for orientation. The right result can change with the service model and current rules.
If the MSA says it prevails, can we ignore the PO quality annex?
Not safely. A specific quality protocol attached to a performed PO is often treated as the deal the parties actually ran, unless you objected in time.
Do we need a PO if the MSA is detailed?
You still need a clear ordering mechanism for quantity, SKU and delivery dates. Otherwise you argue about whether a WeChat request was an order.
Primary authorities
Reviewed sources support orientation, not a fact-specific assessment.