before the fix:
##### With input 30 Digits Integer #####
Name ips average deviation median 99th %
Decimal.add() Int 318.01 K 3.14 μs ±771.75% 3 μs 5 μs
Memory usage statistics:
Name Memory usage
Decimal.add() Int 4.26 KB
**All measurements for memory usage were the same**
##### With input 6 Digits Integer #####
Name ips average deviation median 99th %
Decimal.add() Int 903.01 K 1.11 μs ±3457.31% 1 μs 2 μs
Memory usage statistics:
Name Memory usage
Decimal.add() Int 592 B
**All measurements for memory usage were the same**
##### With input 606 Digits Integer #####
Name ips average deviation median 99th %
Decimal.add() Int 43.65 K 22.91 μs ±73.77% 22 μs 44 μs
Memory usage statistics:
Name Memory usage
Decimal.add() Int 3.73 KB
with the fix:
##### With input 30 Digits Integer #####
Name ips average deviation median 99th %
Decimal.add() Int 316.97 K 3.15 μs ±659.73% 3 μs 5 μs
Memory usage statistics:
Name Memory usage
Decimal.add() Int 4.26 KB
**All measurements for memory usage were the same**
##### With input 6 Digits Integer #####
Name ips average deviation median 99th %
Decimal.add() Int 930.26 K 1.07 μs ±3092.95% 1 μs 2 μs
Memory usage statistics:
Name Memory usage
Decimal.add() Int 592 B
**All measurements for memory usage were the same**
##### With input 606 Digits Integer #####
Name ips average deviation median 99th %
Decimal.add() Int 43.93 K 22.77 μs ±29.74% 22 μs 39 μs
Memory usage statistics:
Name Memory usage
Decimal.add() Int 3.73 KB
As you can see the cost in this case is not relevant. 
