How to explain that some phrases sound more informal/casual in a business context than others?

Question

I am having a hard time phrasing my question in just one sentence, so I'll try to give it some context. I work in an non-English speaking country, so my colleagues tend to use phrases that are non-colloquial.

This is not such a big deal, except sometimes they use phrases that could be misunderstood. For example, a colleague made a graph of mobile phone calls per person and named it "Customers who talk on the phone a lot". Another made a graph of customer service calls per person and named it "Rate of customers who call customer service a lot"

I want to articulate to them that the phrase "talk a lot" has other, possible negative connotations (e.g., excessive talking) and that a (marginally) better title would be "frequent users of mobile phone calls" or "Frequent callers to customer services" (if anyone has alternative suggestions that would be great!) Is there any grammatical/linguistic basis that I could refer to when I bring this up?

Answer 1

I would call the first graph "Calls per customer" and the second graph "Calls to customer service per customer."

The wording that refers to customers who talk or call a lot implies that the customers who don't make a lot of calls are omitted from the graphs. I'm assuming that they are included in the graphs.