No, not in this context. "Most iOS devices are not iPhones" is an accurate statement. It's also accurate in attempting to get the point across: iOS doesn't necessarily mean iPhone, and that iPhone isn't the only source of iOS platform that should be considered.

It's like the idea of significant. All too often, people confuse significant with majority. This is not the case. Significant rarely means majority, except when used in the all too cumbersome "significant majority".

Finally, most people would agree even a 5% different is a significant difference. =)