Maybe we are reading too much into the number... but 76 is oddly specific.

I believe EIS2 was introduced in circa 2002, not sure how long the overlap was before EIS2 become standard, quick internet search tells me it was 2004, and a FAST magazine article about A330 mentioned that EIS2 was developed alongside A340-5/600, and introduced to the A330 in 2003.

AC mainline currently has 5 A319, 16 A320 (+ 2 incoming) and 16 A321
AC Rouge has 18 A319, 5 A320 and 17 A321.
Jetz has 4 A320

that brings us to total of 83 planes, as Expressflyer900 mentioned, many newer later fins already had EIS2 installed and the mainline A319 that are likely not going to be around in the future.

Breaking them down by the year,

EIS1 (Pre 2003)

• All Rouge A319 (18)
• All Mainline A319 (5)
• Mainline A320 (8, fin 235,236,237,241,401,402,405,415)
• All Jetz A320 (4)
• Mainline A321 (12, fin 451,452,453,454,455,456,457,458,459,460,464,473)

Not sure (2003-2004)

• Mainline A320 (4, fin 238,239,240,242) - Likely to be EIS1 given there are ordered from the same batch with the pervious fins

EIS2 (post 2004)

• All of Rouge's A320 (5)
• All of Rouge's A321 (17)
• Mainline A320 (6, fin 417,418,419,420,421,422)
• Mainline A321 (4, fin 461,462,463,483)

So, there are at most 51 fins, quite a bit short of the 76 aircrafts.

According to Thales, EIS2 screens share the same part number from A318 to A340....
It also make sense to retrofit their original A330, that would bring our numbers up to 59. Still don't quite add up.

Maybe they are trying to bring in more vintage A320 from various sources? we are probably just reading too much into that number...
Could be the funds allocated to this contract can cover up to 76 aircrafts.