A client change can change what the result measures
In ordinary stable gameplay, a successful slider head has more forgiving accuracy requirements than a hit circle. Lazer judges slider-head timing; ScoreV2 and Classic settings require separate consideration. If accuracy drops mainly on slider-heavy maps after switching, inspect head judgements before concluding that all of your timing deteriorated. Treat circle-only sections as a useful comparison, not as proof that the clients behave identically.
Classic mod is not classic score display
Lazer's Classic mod restores selected legacy behaviours. Its classic score display is a different setting: it changes how score totals are presented, not a switch back to stable's complete gameplay rules. The official migration guide also documents grading changes that Classic does not undo. Compare the actual mod settings, judgements and scoring display rather than assuming that matching the word Classic makes two results interchangeable.
Troubleshoot one difference at a time
First confirm the exact beatmap version, then record rate, AR, OD and enabled mod settings. Next check audio and input settings against your old setup; do not assume migration copied every preference. Choose a familiar difficulty with both circles and sliders. Compare several attempts and note whether the change appears throughout the map or mainly on slider entries. Avoid changing offset, skin and mod settings together, which would obscure the comparison.
Use a small comparison sheet
Suggested columns: client, score date, difficulty ID, mods with settings, displayed score type, accuracy, misses and slider-head observations. Keep a stable play, a lazer play and any Classic experiment on separate rows. If only raw score differs, first check the score display rather than treating it as lost skill. If circle judgements remain similar but slider heads worsen, practise their entries and check another slider-heavy map before judging progress.
Keep original results and current documentation
An imported old play is not a new performance under your current setup. Preserve its original context and avoid averaging it with new attempts to make a single accuracy trend. For progress, compare a consistent group of plays within one setup, then describe cross-client differences separately. Use the official migration guide for current compatibility details; an old video or feature checklist may describe a different lazer release.
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