ONE
Even in canon, there were 2x Federation-Klingon wars within 10 years of each other.
One started in 2257, the other in 2267.
And the timeline has changed.
Assuming that things are going to be all smooth sailing is asking to get got.
TWO
The numbers do not make sense for not going Covariant.
Quick math
TRANCHE 1
The cost delta between a ship with Type-1 Heavy Standards(97.25) and Type-1 Standard Covariant(104.75) is 7.5 points
Thats 7.7% increase.
Same shield strength.
The cost delta between a ship with Type-1 Heavy Standard(97.25) and Type-1 Heavy Covariant(116.75) is 19.5
Thats roughly 20% cost increase.
And +8 Shields
TRANCHE 2
The cost delta between a ship with Type-1 Heavy Standards(91.25) and Type-1 Standard Covariant(93.75) is 2.5 points
Thats a 2.7% cost increase.
The cost delta between a ship with Type-1 Heavy Standard(91.25) and Type-1 Heavy Covariant(103.25) is 19.5
Thats roughly 13% cost increase
And +8 Shields
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I can see an argument for going with Standard Covariant over Heavy Covariant.
I cannot see a financial case for taking the Type-1 Heavy.