Hello,
The throughput depends on all the factors(FrameSize, SPP_RxBufferSize, SPP_TxBufferSize and Baud rate) but once you hit a bottleneck with the MTU increasing the baud rate will not increase the throughput. However, your TX_Throughput is a bit low. We'll test with your parameters and get back to you.
Please take a look at this document as well if you already have not, processors.wiki.ti.com/index.php/CC256x_Bluetopia_Throughput
Best Regards,
Stonestreet One