Thank you a lot. I didn't know the different. For Cold-Walltet, addmultisigaddress shouldn't be used.
I agree both should generate the same address, otherwise those are different as long as I tested.

Thank you so much for your pointing out as well.

That address was generated by "addmultisigaddress". Actually, it was different from generated by "createmultisig".
Not yet understanding the difference but, will use "createmultisig" as well as the original of Bitcoin Developer Examples.

There were not so particular deep meaning for using "addmultisigaddress". Just consisted getting account for confirming "sendmany".

Thank you so much for your pointing out. It's notified me that my recent trials were not for Cold Wallet operation.
I did as blew, and worried wastefully.

1. Get 3 address and the relative pubkey and privkey at an online node.
2. In the same online node, get multig address from above 3 relative pubkey.
3. In the same online node, try "sendmany" by setting account of the multisig address to the from.

At the actual operation, we should remove the node used for generate multisig address and relatives, to be the address Cold.
Thus, because of losing the base node, sendmany cannot be used for spending allocation of the multisig account.

I've tried Bitcoin Developer Examples again, and confirmed the "P2SH Multisig" part does work without online node of multisig.

My team is going to make Multisig type Cold Wallet, which needs more than 2 offline individual signature at spending from.

We referred the following page for it, and found the rough step will be 1."createrawtransaction", 2.(multiple)"signrawtransaction", and 3."sendrawtransaction".

Bitcoin Developer Examples
https://bitcoin.org/en/developer-examples

However, this multiple signature process could be skipped by using "sendmany" on bitcoin-cli.
The following history is what I tested on testnet-3 today. "multisig" is our P2SH multisig address account for test.

---
bitcoin-cli getbalance multisig
0.87023010
---
bitcoin-cli sendmany "multisig" '''{"2N6ptYtQDBQXCM4xKAFbWHo5ZZkT1PJTaEe":0.1,"2MwZKfMuSNbe4i1TxTYAdGFshvZoMg1bmo5":0.2}'''
6b1a1b4ab4db30023ae7d38e221e3a6addfb669d33c9db36d7b671ebfa320d07
(https://live.blockcypher.com/btc-testnet/tx/6b1a1b4ab4db30023ae7d38e221e3a6addfb669d33c9db36d7b671ebfa320d07/)
---
bitcoin-cli getbalance multisig
0.57018090
---
bitcoin-cli validateaddress 2N7FBhWJb6JW9RrmhGvCRi7XN3yCD58Nd1j
{
  "isvalid": true,
  "address": "2N7FBhWJb6JW9RrmhGvCRi7XN3yCD58Nd1j",
  "scriptPubKey": "a914998fd9987bd33c512c8466e44e12b745586803f387",
  "ismine": true,
  "iswatchonly": false,
  "isscript": true,
  "iswitness": false,
  "script": "witness_v0_scripthash",
  "hex": "0020ff22a320dac7662375c449420bbc9d4a72d3bd5855ed1ba6ff6e0ac2acddba1d",
  "embedded": {
    "isscript": true,
    "iswitness": true,
    "witness_version": 0,
    "witness_program": "ff22a320dac7662375c449420bbc9d4a72d3bd5855ed1ba6ff6e0ac2acddba1d",
    "script": "multisig",
    "hex": "5221029e1a7ae1a9c923e139a9bc15391ec14cad370e0a3d8e171b50a6614ee8d165ba210368e5b fb5cf02a5468a9e998f44f7abb6303550e072cf33a5e3ed275752fe30462102f75140c0054f856a 1e4f8a553f437a8d42ecbfc6fa3f48030ce73176ff450b2b53ae",
    "sigsrequired": 2,
    "pubkeys": [
      "029e1a7ae1a9c923e139a9bc15391ec14cad370e0a3d8e171b50a6614ee8d165ba",
      "0368e5bfb5cf02a5468a9e998f44f7abb6303550e072cf33a5e3ed275752fe3046",
      "02f75140c0054f856a1e4f8a553f437a8d42ecbfc6fa3f48030ce73176ff450b2b"
    ],
    "address": "tb1qlu32xgx6canzxawyf9pqh0yaffed802c2hk3hfhldc9v9txahgwssuemns",
    "scriptPubKey": "0020ff22a320dac7662375c449420bbc9d4a72d3bd5855ed1ba6ff6e0ac2acddba1d"
  },
  "addresses": [
    "tb1qlu32xgx6canzxawyf9pqh0yaffed802c2hk3hfhldc9v9txahgwssuemns"
  ],
  "account": "multisig"
}
---

If my current understanding is correct, Multisig type Cold Wallet, which needs more than 2 offline individual signature at spending from, cannot be made, because the multiple signature process could be skipped by "sendmany" (or "sendfrom").

So, I'd like to get your pointing out if any misunderstanding. We need to make Multisig type Cold Wallet at any risk.