Questions about the value of pc+4 per fetch pc

The book on arm often says that because of the pipelining feature, when the program counter is read during instruction execution, the read value needs to be the current instruction +4

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The program counter (PC) always points to the "fetching finger" instruction

Since arm is a Level 3 pipeline, when the nth instruction is being executed, the n+2 instruction is actually being evaluated, when the PC is pointing to n+2 ~ ~

Because the processor is in the thumb state, each instruction is 2 bytes, so the PC = position of the current execution instruction + 4

Arm state, since each instruction is 4 bytes (32 bits), so pc = position of the current execution instruction + 8

Questions about the value of pc+4 per fetch pc