Two clubs can play the same sport under different match formats. The difference often comes from competition documents rather than a contradiction in the core laws.
Start with the current World Bowls laws
The Laws of the Sport define core play, equipment, scoring, duties and dispute procedures. World Bowls publishes the Crystal Mark Fourth Edition and its revision information on its laws page. Use that page rather than an old screenshot of a rule.
Add domestic regulations
World Bowls allows member national authorities to make domestic regulations in specified areas. Those can address local practices such as substitution requirements or approved measuring equipment. Find the current document for the country in which the match is played.
Read the conditions of play
A competition’s controlling body sets conditions such as match format, number of ends, time limits, dress or tie resolution where permitted. Check the event’s published conditions before assuming a familiar club format applies.
Make a one-page match brief
Before play, write down the format, bowls per player, scoring target, trial ends, time limit, extra-end procedure and who decides disputes. Share the same brief with opponents, marker and scorekeeper.
Source: World Bowls laws and guidance on domestic regulations. Check your national regulations and event conditions before a competitive game.
If a rule seems surprising, ask which document governs that exact match.
For a shared view of close heads, try WGTS for iPhone or WGTS for Android. Use the official measuring procedure whenever your competition requires it.