This table shows how to use the items you entered to achieve maximum level for your original gear. The value listed in each column (besides result) shows the value of the item you should use as infusion fuel next. The row highlighted in green shows the recommended infusion path (pretty much the highest number you can achieve in the fewest amount of moves possible).

To follow this table, infuse your original item with the item in 'step 1', if you wish to do more infusions, infuse the item in 'step 2' and so on, in to the result from the previous step.

This allows you to chose if doing an extra infusion is worth the extra cost (legendary marks, etc)