FSP is not allowing to enable few interrupts of SPI1 after defining stacks of 4 Uarts(16 interrupts) +2 I2C(8 interrupts) + 1 SPI0(4 Interrupts)

I am using RA2L1 series and FSP 3.5.0 . As its my observation when I use nearly up to 28 interrupts (weather it is of GPT, UART, SPI I2C no matter) no problem seen, but using new stack, not allowing to enable further few interrupts of same stack. 

Do I need to do it manually or its really conflicting?