There is normalcy where the plate voltages are fed through the output transformer with one stage of filtering, 20uf capacitor. There is a choke and another 20uf filter that feeds the screens voltages which is not unusual either. Then there is the center tap of the heater circuit which ties directly to the cathodes, which is maybe where your having confusion? You'll see a 250 ohm cathode resistor with a 20uf cathode bypass cap which goes to ground, which is normal. The only semi-different thing there is the center tap of the heaters connected directly to the cathodes. Which I believe just elevates the heater circuit to a DC voltage rather than ground or zero volts. This helps reduce hum or buzz related to the heater circuit.