The database in use is MySQL.
Here is a small subset of the data creating the problems, entry 17 will produce the problem every time.
If I change the value to 96.9, then it writes to the PLC array element.
But some numbers are simple decimals and they will produce the same problem.
In this subset that I provided, you will notice 3 or 4 others that create the same problem.
The database use double as the floating point data type. (Standard SQL92). Of course the PLC uses FLOAT32. So, I did suspect that there are conversion going on, but really that is a simple casting in your programming environment, which is part of the compiler that you use to build your application, so I ruled that out. Unless you are doing something non-standard. Other compiles with do this automatically, without your interaction.
1 5.69999980926514
2 11.3999996185303
3 17.1000003814697
4 22.7999992370605
5 28.5
6 34.2000007629395
7 39.9000015258789
8 45.5999984741211
9 51.2999992370605
10 57
11 62.7000007629395
12 68.4000015258789
13 74.0999984741211
14 79.8000030517578
15 85.5
16 91.1999969482422
17 96.9000015258789