The recurring obligations are the product
A Hong Kong company must have a company secretary who is resident in Hong Kong, and a registered address in Hong Kong, every year for as long as it exists. A non-resident founder cannot do either personally.
That is the whole reason this market exists, and it is why comparing agents on the incorporation fee alone is a mistake. You are signing up to an annual relationship. Ask what year two costs before you pay for year one, and note that only BBCIncorp on this page publishes that number without being asked.
The audit nobody budgets for
Hong Kong requires an annual audit by a local CPA. It applies to almost every company, including many dormant ones, and it is not included in any of the incorporation packages above.
This is the most common reason a Hong Kong company turns out to cost more than the founder planned. Before choosing on a USD 745 versus USD 1,070 formation fee, get an audit quote, because it will usually be larger than the gap between them.
Territorial does not mean automatic
Hong Kong taxes profits sourced in Hong Kong. Profits genuinely sourced elsewhere can fall outside the charge, and that is a real and legitimate feature of the system.
It is not automatic, and it is not a filing box you tick. An offshore claim is examined by the Inland Revenue Department and needs to be supported by where the work was actually done, where contracts were negotiated and where decisions were taken. Agents that present this as a default outcome of incorporating in Hong Kong are describing a marketing position, not the law.