The arithmetic
For each habitat row in the JP039 spreadsheet, baseline units = distinctiveness x condition x area x strategic significance. Sum across rows to get total baseline units. The post-development units must reach baseline x 1.10 after the post-dev habitats have been scored on the same multipliers plus the temporal, spatial, and difficulty risk multipliers.[S1]
Why the uplift applies after multipliers
Applying the 10% to the headline area would understate the biodiversity value lost; high-distinctiveness habitat loses more units per hectare than commodity grassland. The metric is designed so the uplift compensates for the quality of what is lost, not just the quantity.
LPA power to require more
The 10% is a statutory minimum; LPAs may set local policy at higher levels. Lichfield District Council adopted a 20% requirement in policy; Cornwall Council has signalled intent for higher in coastal NCAs. The LPA policy lookup page tracks adopted local policies.[S12]
Rounding rules
The metric does not round at intermediate steps; the final delta is reported to two decimal places. A scheme returning 9.99% on the JP039 spreadsheet does not satisfy the 10% requirement; an additional fractional BU must be delivered or purchased.