Humans feel much better while walking in winter wearing a fleece with wind breaker and snug tight to the body. Comparing this to house, insulation works better with no holes or gaps in the attic floor. Home owners should know nsulation does not stop air movement. All the black spots on the existing insulation due to air infiltration or exhilaration and insulation is acting as filter. The insulation R-value is greatly reduced due to air movement.
Our approach is to seal the attic floor with expandable foam insulation along the edges and MEP penetrations first and then add more insulation to bring to R-49.