create a variable to record the enchant level:

Code (Text):

1.  
2. variables:
3.     {fortune.%player%} = 0
4.  
5. command /debug:
6.     trigger:
7.         set {fortune.%player%} to 2
8.  
9. on break:
10.     if {fortune.%player%} is not 0:
11.         set {_x} to {fortune.%player%} * 2 - 1 #Remove the - 1 if you cancel the event
12.         drop {_x} of event-block #or give {_x} of event-block

 

This maybe?

Code (Text):

1.  
2. variables:
3.     {fortune.%player%} = 0
4.     {fortunemax} = 5
5.  
6. command /debug:
7.     trigger:
8.         set {fortune.%player%} to 5
9.  
10. command /upgrade: #Assuming you had a similar command
11.     trigger:
12.         if player's held item is a pickaxe:
13.             set {_x} to 0
14.             loop {fortunemax} times: # Amount of levels
15.                 if {fortune.%player%} is {_x}:
16.                     add 100 to {_fortunecost.%{_x}%}
17.                     if {money.%player%} is greater than {_fortunecost.%{_x}%}:
18.                         add 1 to {fortune.%player%}
19.                         set lore of player's tool to "&7Fortune %{fortune.%player%}%"
20.             add 1 to {_x}
21.  
22. on break:
23.     if player's gamemode is not creative:
24.         cancel event
25.         if event-block is diamond ore:
26.             set {_x} to 0
27.             loop {fortunemax} times:
28.                 if lore of player's held item contains "Fortune %{_x}%":
29.                     set {_v} to {fortune.%player%} * 2
30.                     give {_v} of diamond to player
31.                     add 1 to {_x}
32.  

 

It doesn’t need to “read” the lore because of the variable {fortune.%player%}