Discrepancy in storage slot calculation for array of structs, or not?

[0xScratch]

Tags: @naddison36 @Nabeel-javaid

I was using sol2uml to calculate the storage slots of the Store contract (code below), which can also be found here. This contract is straightforward, with a payments struct, some storage variables, etc. The part that requires our focus is the array of structs topPayments.

// SPDX-License-Identifier: UNLICENSED
pragma solidity ^0.8.13;

contract Store {

    struct payments {
        bool valid;
        uint256 amount;
        address sender;
        uint8 paymentType;
        uint256 finalAmount;
        address receiver;
        uint256 initialAmount;
        bool checked;
    }
    uint8 index;
    uint256 public number;
    bool flag1;
    address admin;
    mapping (address=>uint256) balances;
    bool flag2;
    address admin2;
    bool flag3;
    payments[8] topPayments;


    constructor(){

    }


    function setNumber(uint256 newNumber) public {
        number = newNumber;
    }

    function increment() public {
        number++;
    }
}

After creating a .svg for this contract using sol2uml. We get this:

As you can see, topPayments takes 1792 bytes, which is correct since each payment struct covers 7 slots, equivalent to 224 bytes each. Thus, 224 * 8 = 1792 bytes, fairly simple. But as we move to the next step and spot this:

Here 4 struct elements are represented individually and allotted 224 bytes, there's no doubt in that. But the rest 4 (in the middle) are actually allotted 928 bytes which seems quite inappropriate as 224 * 4 = 896 bytes. Due to this, the whole summation becomes 1824 bytes (896 + 928).

And, we can clearly see 1792 != 1824, which makes me assume either sol2uml is wrong here or there's something that I missed in this scenario.

Hope you guys can help me out...

Thanks!