C:\test>1162861.pl
[
  undef,
  undef,
  undef,
  undef,
  [undef, 0.1, 0.2, 0.3],
  [undef, 0.4, 0.5, 0.6],
  [undef, 0.7, 0.8, 0.9],
]

[
  [0.1, 0.2, 0.3, 0.3],
  [0.4, 0.5, 0.6, 0.6],
  [0.7, 0.8, 0.9, 0.9],
  [0.7, 0.8, 0.9, 0.9],
]

0.75515