See the ideal panel tilt for your latitude, and how much your actual roof pitch costs (or gains) you in production.
A deviation this small is well within normal range — no need to change your mounting.
This is a simplified, widely used planning rule — not a full solar-position model. Real installers use software like PVsyst or PVGIS/PVWatts to model your exact site, but the latitude rule gets you within a few percent for almost any roof, which is why it's still the standard first estimate in the industry.
Usually only if you're far from your optimal angle and have room to avoid inter-row shading between tilted rows — a small tilt frame (10-15°) is common on flat commercial roofs even without hitting the "ideal" number exactly.
Often yes. A south-facing (or north-facing in the southern hemisphere) roof at a non-ideal tilt usually outproduces an east/west roof at a "perfect" tilt — orientation is typically the bigger lever.
Yes — "roof angle," "tilt," and "solar panel angle" all refer to the same measurement here: the angle between the panel surface and the horizontal ground. The latitude-based estimate above gives you that panel angle directly, in degrees, for year-round, summer-biased or winter-biased optimization.