I've been spending some time in the 1940's with some research and have been able to confirm these new additions to the boys' side of the Record Book!
Largest Average Margin of Victory
(B) 32.2 Reitz 2014-15
(B) 31.9 Darlington 1969-70
(B) 31.6 Hebron 1989-90
(B) 30.6 Lawrenceburg 1948-49
(B) 30.0 Muncie Central 1959-60
(B) 28.8 North Judson 1994-95
(B) 28.8 Darlington 1968-69
(B) 28.3 New Castle 1948-49
(B) 28.2 EC Washington 1970-71
(B) 27.7 Bloomington North 1999-00
(G) 34.6 SB Washington 2008-09
(G) 33.8 TH South 2000-01
(G) 31.8 Ben Davis 2009-10
(G) 31.3 Columbus North 1974-75
(G) 31.0 Hamilton Heights 2010-11
(G) 30.5 Gavit 2009-10
(G) 29.8 Ben Davis 2008-09
(G) 29.6 Wabash 2010-11
(G) 29.6 FW Canterbury 2011-12
(G) 29.5 Franklin County 2000-01
Lowest Defensive Average for a Season
(B) 20.4 TH Garfield 1946-47
(B) 27.7 Concord Twp. 1948-49
(B) 28.3 Marion 1946-47
(B) 33.3 Jimtown 2006-07
(B) 33.4 Cass 2003-04
(B) 33.6 Norwell 2005-06
(B) 34.4 Providence 2012-13
(B) 35.0 Jay County 2011-12
(B) 35.1 Cass 2002-03
(B) 35.7 Jay County 2012-13
(G) 26.5 Indy International 2011-12
(G) 27.0 Southwood 1973-74
(G) 28.0 Hagerstown 2011-12
(G) 28.0 Jimtown 2009-10
(G) 28.9 Jimtown 2007-08
(G) 29.5 Turkey Run 2010-11
(G) 30.1 Jimtown 2008-09
(G) 30.3 Jeffersonville 1973-74
(G) 30.4 Gavit 2009-10
(G) 30.9 Hagerstown 2009-10
(G) 30.9 Hagerstown 2006-07
Largest Average Margin of Victory
(B) 32.2 Reitz 2014-15
(B) 31.9 Darlington 1969-70
(B) 31.6 Hebron 1989-90
(B) 30.6 Lawrenceburg 1948-49
(B) 30.0 Muncie Central 1959-60
(B) 28.8 North Judson 1994-95
(B) 28.8 Darlington 1968-69
(B) 28.3 New Castle 1948-49
(B) 28.2 EC Washington 1970-71
(B) 27.7 Bloomington North 1999-00
(G) 34.6 SB Washington 2008-09
(G) 33.8 TH South 2000-01
(G) 31.8 Ben Davis 2009-10
(G) 31.3 Columbus North 1974-75
(G) 31.0 Hamilton Heights 2010-11
(G) 30.5 Gavit 2009-10
(G) 29.8 Ben Davis 2008-09
(G) 29.6 Wabash 2010-11
(G) 29.6 FW Canterbury 2011-12
(G) 29.5 Franklin County 2000-01
Lowest Defensive Average for a Season
(B) 20.4 TH Garfield 1946-47
(B) 27.7 Concord Twp. 1948-49
(B) 28.3 Marion 1946-47
(B) 33.3 Jimtown 2006-07
(B) 33.4 Cass 2003-04
(B) 33.6 Norwell 2005-06
(B) 34.4 Providence 2012-13
(B) 35.0 Jay County 2011-12
(B) 35.1 Cass 2002-03
(B) 35.7 Jay County 2012-13
(G) 26.5 Indy International 2011-12
(G) 27.0 Southwood 1973-74
(G) 28.0 Hagerstown 2011-12
(G) 28.0 Jimtown 2009-10
(G) 28.9 Jimtown 2007-08
(G) 29.5 Turkey Run 2010-11
(G) 30.1 Jimtown 2008-09
(G) 30.3 Jeffersonville 1973-74
(G) 30.4 Gavit 2009-10
(G) 30.9 Hagerstown 2009-10
(G) 30.9 Hagerstown 2006-07