I don't have a SDM3065X but did test out the SDM3045X. The device will reset data only if the data option is set to recent rather than all. This option is the second soft button when in trend display mode. When all is selected, I have no problems with accumulating data when I switch display modes. I also tested this using EasyDMM and it behaved the same.
A couple of caveats that I didn't care for with EasyDMM:
1) It will reset the device accumulation upon connection in Data Mode.
2) It seemed to cause my device to hang at one point, where I had to cycle power. (I could not get the device back to local control mode)
3) At one point a few minutes in, the EasyDMM reported a query error and was not updating. The device was still collecting, but upon reconnecting with EasyDMM, it reset the data. Not cool.
4) EasyDMM (and maybe other EasyTools) are saving files with a .bmp extension, but are really .jpgs. This causes problems with this forum, as it thinks the files are corrupt!
The first image shows where the option is. The second shows the data accumulating across the display mode change. The other images show Trend in EasyDMM and data and graphing using the app as well.
*** UPDATE ***
Testing the SDM3055 as well (both having latest firmware), it behaves just like the SDM3045X.