Why identical swaps from two wallets can cost different amounts

Two wallets can submit the same token amount and still face different preparation or execution costs. Match their relevant state before concluding that the interface prices users differently.

Compare the complete task

Suppose hypothetical Wallet A has a usable allowance and needs only a $0.60 swap transaction. Wallet B needs a $0.40 approval before the same $0.60 swap. The immediate cost is $0.60 for A and $1.00 for B, even if the token execution quote is identical.

The difference is preparation state, not necessarily a worse exchange rate for B. Reporting only the swap receipt would hide B's additional spending.

State variables to record

• Whether the input-token allowance is usable by the selected spender.
• Whether the account needs deployment, initialization or another setup operation.
• Whether the service offers a user-specific subsidy or payment arrangement.
• Whether the final transaction route and recipient operations actually match.

ERC-20 allowance state belongs to the owner-spender relationship. An allowance available to one wallet says nothing about another wallet's authorization.

Use appropriate comparison labels

A first-use user-experience comparison can deliberately include each wallet's actual setup. A router-efficiency comparison should hold that setup boundary constant. Neither is inherently wrong, but they answer different questions.

Do not compare a smart-account operation with a plain-account transaction using only the displayed gas limit; their accounting boundaries can differ. Retain the actual user payment and final token receipt for an economic comparison.

Once relevant states match, any remaining gap still needs investigation of timing, route, fee terms and valuation. State differences offer plausible explanations, not automatic proof of the cause. Record what is known rather than assuming every difference is an approval or every unexplained difference is discriminatory pricing.