The code allows up to 6 disconnects on a service.
"230.71 Maximum Number of Disconnects
(A) General The service disconnecting means for each service permitted by 230.2, or for
each set of service-entrance conductors permitted by 230.40, Exception Nos. 1, 3, 4, or 5,
shall consist of not more than six switches or sets of circuit breakers, or a combination of
not more than six switches and sets of circuit breakers, mounted in a single enclosure, in
a group of separate enclosures, or in or on a switchboard. There shall be not more than
six sets of disconnects per service grouped in any one location. For the purpose of this
section, disconnecting means used solely for power monitoring equipment, transient
voltage surge suppressors, or the control circuit of the ground-fault protection system or
power-operable service disconnecting means, installed as part of the listed equipment,
shall not be considered a service disconnecting means."
Older panels had Split Busses. But this is still allowed in the code. Now days it is more often applied to multiple panels for 400 amp service or mutliple disconnects in one panel for multiple tenent buildings.
A Split Bus panel is one that does not have a main disconnect. Rather one disconnect/overload is used to supply a in internal bus for the 120 loads and other disconnects/overloads for the larger 240 loads.
I have not seen a fuse panel like yours.
The 7th from the right is a style tht is more common.
The pullout on the left is for all of the 120 load connected to the 8 fuses bock (of which only 6 are used) on the bottom.
The rigth pullout is used for the stove. There is no common disconnect.
Not sure what the 4 fues in a row are for. It has been 40 years since I looked at one. Possibly for WH and Dryer and off "main" disconnect.
I have no idea how yours is arranged.
But there is no problem pulling out or replacing a block with the power on.
However, it prevent arching the current should be zero or low.
In your case that just means to turn off or unplug the dyer first.