STM32cubemx PWM + ADC DMA out of sync - stm32

Question

I'm trying to get STM32F103 to work with ADC and DMA both in circular mode to perform DSP processing in a basic way (see picture).
DMA fills ADC buffer, on "ADC half full" interrupt we process samples inBuffer[0..half] and put it in outBuf[0..half].
Output buffer is also fed to timer-driven PWM via DMA.
My thought is: TIM1 prescaller is (2-1), period is (1024-1), which with 72MHz timer clock has to make 35156 kHz 10-bit PWM. With buffer length of 512 samples buffer is 14,5ms long. I wait for DMA to sample 256 samples every 7,25ms, pushing out 256 samples to PWM in total pointer-to-pointer sync.
The problem is that I'm not sure if ADC and PWM buffer are syncronised.
With following code i get this:
void dspStart(void){
HAL_TIM_Base_Start(&htim1); // start timer
HAL_TIM_PWM_Start(&htim1, TIM_CHANNEL_2); //start PWM which triggers ADC
HAL_ADC_Start_DMA(&hadc1, (uint32_t*)inBuf, ADC_BUFFER_LEN); // start DMA w/ ADC
HAL_TIM_PWM_Start_DMA(&htim1, TIM_CHANNEL_3, (uint32_t*)outBuf, ADC_BUFFER_LEN); // start PWM output
}
void HAL_ADC_ConvHalfCpltCallback(ADC_HandleTypeDef* hadc1){
HAL_GPIO_TogglePin(GPIOB, GPIO_PIN_3); // yellow channel
}
void HAL_ADC_ConvCpltCallback(ADC_HandleTypeDef* hadc1){
HAL_GPIO_TogglePin(GPIOB, GPIO_PIN_3); // yellow channel
}
void HAL_TIM_PWM_PulseFinishedHalfCpltCallback(TIM_HandleTypeDef *htim1){
HAL_GPIO_TogglePin(GPIOB, GPIO_PIN_4); // blue channel
};
void HAL_TIM_PWM_PulseFinishedCallback(TIM_HandleTypeDef *htim1){
HAL_GPIO_TogglePin(GPIOB, GPIO_PIN_4); // blue channel
}
ADC and PWM buffers are out of sync, although buffer size is same for both DMA channels and they share same TIM1.
What did I do wrong?
STM32cubeMX setting are following: