Correct IF formula:
=if(j4=1,sum('Upgrades-Beta'!b76:'Upgrades-Beta'!b100),
if(j4<3,sum('Upgrades-Beta'!b77:'Upgrades-Beta'!b100),
if(j4<7,sum('Upgrades-Beta'!b78:'Upgrades-Beta'!b100),
if(j4<11,sum('Upgrades-Beta'!b79:'Upgrades-Beta'!b100),
if(j4<15,sum('Upgrades-Beta'!b80:'Upgrades-Beta'!b100),
if(j4<19,sum('Upgrades-Beta'!b81:'Upgrades-Beta'!b100),
if(j4<23,sum('Upgrades-Beta'!b82:'Upgrades-Beta'!b100),
if(j4<27,sum('Upgrades-Beta'!b83:'Upgrades-Beta'!b100),
if(j4<31,sum('Upgrades-Beta'!b84:'Upgrades-Beta'!b100),
if(j4<36,sum('Upgrades-Beta'!b85:'Upgrades-Beta'!b100),
if(j4<41,sum('Upgrades-Beta'!b86:'Upgrades-Beta'!b100),
if(j4<46,sum('Upgrades-Beta'!b87:'Upgrades-Beta'!b100),
if(j4<52,sum('Upgrades-Beta'!b88:'Upgrades-Beta'!b100),
if(j4<58,sum('Upgrades-Beta'!b89:'Upgrades-Beta'!b100),
if(j4<64,sum('Upgrades-Beta'!b90:'Upgrades-Beta'!b100),
if(j4<70,sum('Upgrades-Beta'!b91:'Upgrades-Beta'!b100),
if(j4<75,sum('Upgrades-Beta'!b92:'Upgrades-Beta'!b100),
if(j4<80,sum('Upgrades-Beta'!b93:'Upgrades-Beta'!b100),
if(j4<85,sum('Upgrades-Beta'!b94:'Upgrades-Beta'!b100),
if(j4<90,sum('Upgrades-Beta'!b95:'Upgrades-Beta'!b100),
if(j4<95,sum('Upgrades-Beta'!b96:'Upgrades-Beta'!b100),
if(j4<100,sum('Upgrades-Beta'!b97:'Upgrades-Beta'!b100),
if(j4<105,sum('Upgrades-Beta'!b98:'Upgrades-Beta'!b100),
if(j4<110,sum('Upgrades-Beta'!b99:'Upgrades-Beta'!b100),
if(j4<115,sum('Upgrades-Beta'!b100),
0)))))))))))))))))))))))))