ok found this the other night, might not be the best thing EVER!!! but its helped me... so upgrading is a right !@#$%^&*, so i bought !@#$%^&* loads of low class upgrade scrolls and loads of +1 weapons... so the upgrade box where u put ur scrolls is diveded into 9 boxes...
[1] [a][b][c]
[2] [a][b][c]
[3] [a][b][c] ...... this is to symbolize the rows and wht box ok
put ur desired weapon in the anvil and put ur first upgrade scroll in row [3] box [c]... then upgrade, and next time put the scroll in [3] box[1]... then [2] box[3] then [2] box[1]...... now buy a high class upgrade scroll or if ur broke use a mid class.. and put it in [1] box[3].... now u should have a+6 weapon... now exit the anvil then go back into it and use a high cls scroll in [1] box [1] and u should get +7 weapon, never failed with me
and to get +8 ur best chance is a blessed upgrade scroll