Index/Match help

ok so it looks like in my fuddling i managed to make my table more complicated and am hoping to solve it none the less.  

i've uploaded the table i'm working on. 

i managed to get it to work one way. but what i would like to do is be able to enter in my Temp and Gravity and have it bring back the Weight the problem is i keep coming up with #n/a 

i'm using the code : 

i was able to get the weight to come up by entering temp and gravity using 

=INDEX($A$2:$D$12, MATCH($G$3,$A$2:$A$12,0), MATCH($G$4,$A$2:$D$2,0))

but i was hoping it would work the other way pulling Temp and Gravity using the following: 

=INDEX($A$2:$D$12, MATCH($H$5,$B$3:$D$12,0), MATCH($G$4,$A$2:$D$2,0))

  Temp        

thanks again for the help