The practical approach
Housing usually deserves its own line because location and property size can overwhelm smaller spending categories. Compare like with like: central versus outer areas and similar bedroom counts.
Food, utilities, transport and household size should be treated separately. A family comparison should not reuse a single-person basket.
Use ranges where the underlying market varies widely. A useful comparison exposes assumptions instead of presenting false precision.
Related questions
Why not just convert the salary using an exchange rate?
Exchange rates convert currencies; they do not account for taxes, housing or household spending.
Should the result be treated as exact?
No. Relocation calculations are planning estimates. Personal tax circumstances and spending choices can materially change the outcome.