I called the frer company

I called them to enquire about the fact that the lines on the test come out so inconsistent. In the morning with fmu the line is super faint, in the afternoon the line is darker. They said that it doesn't matter how strong the line is. That the test is not made to work like that. That as long as there is a line I am pregnant and I shouldn't worry about how strong or faint the line is. What are your opinion?