Ethereum Hypothetical - With 64 execution shards, 960tps for base layer possible?

Is the math on this right, or am I missing something?

Currently, Ethereum is processing ~13.8 trx/sec (https://etherchain.org/).

This will increase ~10% (13.8 trx/sec ~> 15.2 trx/sec) once the merge occurs because block times will drop ~10%. (13.3 sec/block -> 12 sec/block).

For simplicity's sake, let's round the 15.2 trx/sec down to 15 trx/sec.

Now we're at 15 trx/sec with one execution shard. If we add another execution shard, this would add an additional 15 trx/sec. (Basically 1 execution shard = 15 trx/sec.)

If, in theory, we want to increase throughput on the base layer by converting all 64 data shards to execution shards (I'm aware that this is not likely, I'm speaking in hypothetical terms), then 64 execution shards * 15 trx/sec per shard would mean that 960tps is possible on Ethereum's base layer.

Any feedback is welcome.