Building Regs penalty for not air tightness testing a new build on a development

Building Regs Part L1a places a penalty on those dwellings on a development that are not air tightness tested.Green Footsteps blower door testThere should be a figure of +2m3/hm2 @ 50Pa added to the air permeability test result achieved for that dwelling type (Part L1a paragraph 4.8), but I would question whether this always happens in practice…