Wrong estimation of fees for hooks

[anxolin]

Description
I'm observing that SWAPs for hook is not estimating fees correctly.

Facts

In this screenshot you can see the fee for a HOOKS SWAP of 201 COW to xDAI.

In this second screenshot, you can see a NORMAL SWAP of 201 COW to xDAI.

Both fees are the same, however, our hook specified a gas limit of 23,100.

HOOKS REQUEST:

{
    "sellToken": "0x177127622c4a00f3d409b75571e12cb3c8973d3c",
    "buyToken": "0xEeeeeEeeeEeEeeEeEeEeeEEEeeeeEeeeeeeeEEeE",
    "from": "0x79063d9173C09887d536924E2F6eADbaBAc099f5",
    "receiver": "0x79063d9173C09887d536924E2F6eADbaBAc099f5",
    "appData": "{\"appCode\":\"CoW Swap\",\"environment\":\"pr\",\"metadata\":{\"hooks\":{\"pre\":[{\"callData\":\"0x\",\"dappId\":\"c768665aa144bcf18c14eea0249b6322050e5daeba046d7e94df743a2e504586\",\"gasLimit\":\"23100\",\"target\":\"0xfFf9976782d46CC05630D1f6eBAb18b2324d6B14\"}]},\"orderClass\":{\"orderClass\":\"market\"},\"partnerFee\":{\"bps\":10,\"recipient\":\"0x6b3214fD11dc91De14718DeE98Ef59bCbFcfB432\"},\"quote\":{\"slippageBips\":200,\"smartSlippage\":true}},\"version\":\"1.3.0\"}",
    "appDataHash": "0x73ab84e42e0f0c6251e26b30f55f8612bf28246a33a385c37f8b1309334027d7",
    "partiallyFillable": false,
    "priceQuality": "optimal",
    "validFor": 1800,
    "kind": "sell",
    "sellAmountBeforeFee": "201000000000000000000"
}

HOOKS RESPONSE:

{
    "quote": {
        "sellToken": "0x177127622c4a00f3d409b75571e12cb3c8973d3c",
        "buyToken": "0xeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeee",
        "receiver": "0x79063d9173c09887d536924e2f6eadbabac099f5",
        "sellAmount": "200999289982025513046",
        "buyAmount": "110854925167667579123",
        "validTo": 1731000394,
        "appData": "{\"appCode\":\"CoW Swap\",\"environment\":\"pr\",\"metadata\":{\"hooks\":{\"pre\":[{\"callData\":\"0x\",\"dappId\":\"c768665aa144bcf18c14eea0249b6322050e5daeba046d7e94df743a2e504586\",\"gasLimit\":\"23100\",\"target\":\"0xfFf9976782d46CC05630D1f6eBAb18b2324d6B14\"}]},\"orderClass\":{\"orderClass\":\"market\"},\"partnerFee\":{\"bps\":10,\"recipient\":\"0x6b3214fD11dc91De14718DeE98Ef59bCbFcfB432\"},\"quote\":{\"slippageBips\":200,\"smartSlippage\":true}},\"version\":\"1.3.0\"}",
        "appDataHash": "0x73ab84e42e0f0c6251e26b30f55f8612bf28246a33a385c37f8b1309334027d7",
        "feeAmount": "710017974486954",
        "kind": "sell",
        "partiallyFillable": false,
        "sellTokenBalance": "erc20",
        "buyTokenBalance": "erc20",
        "signingScheme": "eip712"
    },
    "from": "0x79063d9173c09887d536924e2f6eadbabac099f5",
    "expiration": "2024-11-07T16:58:34.236950099Z",
    "id": 243207,
    "verified": true
}

SWAP REQUEST:

{
  "sellToken": "0x177127622c4a00f3d409b75571e12cb3c8973d3c",
  "buyToken": "0xEeeeeEeeeEeEeeEeEeEeeEEEeeeeEeeeeeeeEEeE",
  "from": "0x79063d9173C09887d536924E2F6eADbaBAc099f5",
  "receiver": "0x79063d9173C09887d536924E2F6eADbaBAc099f5",
  "appData": "{\"appCode\":\"CoW Swap\",\"environment\":\"pr\",\"metadata\":{\"orderClass\":{\"orderClass\":\"market\"},\"partnerFee\":{\"bps\":10,\"recipient\":\"0x6b3214fD11dc91De14718DeE98Ef59bCbFcfB432\"},\"quote\":{\"slippageBips\":200,\"smartSlippage\":true}},\"version\":\"1.3.0\"}",
  "appDataHash": "0xfd826d6bc0b9dd6a2d64df2e7825de5936dd1c529b17fea04ec5c0c3add57c59",
  "partiallyFillable": false,
  "priceQuality": "optimal",
  "validFor": 1800,
  "kind": "sell",
  "sellAmountBeforeFee": "201000000000000000000"
}

SWAP RESPONSE

{
    "quote": {
        "sellToken": "0x177127622c4a00f3d409b75571e12cb3c8973d3c",
        "buyToken": "0xeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeee",
        "receiver": "0x79063d9173c09887d536924e2f6eadbabac099f5",
        "sellAmount": "200999362564111871644",
        "buyAmount": "110854965198066455234",
        "validTo": 1731000388,
        "appData": "{\"appCode\":\"CoW Swap\",\"environment\":\"pr\",\"metadata\":{\"orderClass\":{\"orderClass\":\"market\"},\"partnerFee\":{\"bps\":10,\"recipient\":\"0x6b3214fD11dc91De14718DeE98Ef59bCbFcfB432\"},\"quote\":{\"slippageBips\":200,\"smartSlippage\":true}},\"version\":\"1.3.0\"}",
        "appDataHash": "0xfd826d6bc0b9dd6a2d64df2e7825de5936dd1c529b17fea04ec5c0c3add57c59",
        "feeAmount": "637435888128356",
        "kind": "sell",
        "partiallyFillable": false,
        "sellTokenBalance": "erc20",
        "buyTokenBalance": "erc20",
        "signingScheme": "eip712"
    },
    "from": "0x79063d9173c09887d536924e2f6eadbabac099f5",
    "expiration": "2024-11-07T16:58:28.760894338Z",
    "id": 243206,
    "verified": true
}

Conclusion

We are underestimating the fee for hooks, but I think I think is likely a FE issue. I can see above how the fee for the SWAP is 0.0006374358881 COW and the fee for the HOOKS SWAP is 0.0007100179745 COW