Rent is always late but tenant pays late dues

[Omow A.]

Hi,

   I have a tenant who for the last 6 months has been paying late rent. I'm not sure if its a problem or a warning sign. This family has rented from me for 4 years and up until last year, was late once a year (December Christmas time). Well, now, I get a very polite text on the 1st, telling me they will be late, will pay on the 10th (14th or whatever date). On the 14th, like clockwork, I get a deposit of FULL rent and late deposit ($50 late plus $20 every late day). This is usually $100-$200 in extra fees. 

    I'm puzzled. Its more expensive for them to pay late but they do. They are good tenants, take decent care of the property. Am I being finicky?