I studied the Physics of Musical instruments in college, and this is absolutely the right answer. String sets for basses are typically designed with an arithmetic progression in string diameter -
45-65-85-105. This results in uneven tension. When extended to a 5th string, this thinking flat out fails. I like really light tension -
40-55-70-95 on a 4 string. A well matched B string for that set is a 130. If you’re playing a 105E, a 140 is what you need. The 120 or 125 in the set you bought is just a bad choice.
35 inch scale is a band aid for the fact that string companies don’t make matched sets - it helps the floppy B somewhat, but makes the other strings tighter as well. With well designed string sets, none of this would be necessary.
I buy single strings to get a well matched B string. It works very well on a 34 inch scale. With the right strings, a 34 inch scale bass is better for a 5 string - shorter necks are, by definition, stiffer. That difference is small, but it is there.