I was told by experts, that there are indeed some compulsory health insurance funds in Germany, which demand the maximum insurance fee based on the social security contribution ceiling ( “Beitragsbemessungsgrenze” ) of 4050 EUR/m income, from any voluntary insured

, even if he/she has much less income

and so would pay just the minimal social security contribution based on a fictive income of 2073.75 EUR/m, at other compulsory health insurances. Indeed some of these compulsory health insurances don´t tell that explicitely at start date of the voluntary insurance, but 2-3 years later when the self-employed gets his/her first approved balance sheet by the finance office

.