No, not more accurate. This looks suspiciously like more tagging for the renderer

Please read the documentation, particularly the part which states that in the UK, highway=trunk applies to "Primary A road (green signs)". This section of the A413 has white signs and was correctly mapped as highway=primary.

https://wiki.openstreetmap.org/wiki/Tag:highway%3Dtrunk

Reverted, obviously. https://www.openstreetmap.org/changeset/154262968