Ok, I get DNA deep dive with R850 as well even though I don't have T1a. Sorry about my own confusion. It terms of distance, I have always been closest to R437 as well. R850 shows up for me in Deep Dive in MyTrueancestry but R437 is always closer for me. Dodecad 12B Ancient. Ok, you get Deep Dive with both R437 and R850, 2 Iron Age Romans.

While I am close to R437 on all calculators, I don't get the Deep Dive match.
[TABLE="class: distances"]
[TR]
[TH="align: right"]Distance to:[/TH]
[TH="align: left"]PalermoTrapani[/TH]
[/TR]
[TR]
[TD="bgcolor: #8EFF00, align: right"]4.18976133[/TD]
[TD]R437_Iron_Age_Palestrina_Selicata[/TD]
[/TR]
[TR]
[TD="bgcolor: #FF3C00, align: right"]13.23641568[/TD]
[TD]R850_Iron_Age_Ardea[/TD]
[/TR]
[TR]
[TD="bgcolor: #FF0035, align: right"]16.54641653[/TD]
[TD]R475_Iron_Age_Civitavecchia[/TD]
[/TR]
[TR]
[TD="bgcolor: #FF0052, align: right"]17.40331865[/TD]
[TD]R1_Iron_Age_Protovillanovan_Martinsicuro[/TD]
[/TR]
[TR]
[TD="bgcolor: #FF00C2, align: right"]20.72008205[/TD]
[TD]R474_Iron_Age_Civitavecchia[/TD]
[/TR]
[TR]
[TD="bgcolor: #E800FF, align: right"]23.17349132[/TD]
[TD]R1015_Iron_Age_Veio_Grotta_Gramiccia[/TD]
[/TR]
[TR]
[TD="bgcolor: #E700FF, align: right"]23.21816315[/TD]
[TD]R1016_Iron_Age_Castel_di_Decima[/TD]
[/TR]
[TR]
[TD="bgcolor: #D300FF, align: right"]23.78614092[/TD]
[TD]R473_Iron_Age_Civitavecchia[/TD]
[/TR]
[TR]
[TD="bgcolor: #9C00FF, align: right"]25.41911682[/TD]
[TD]R1021_Iron_Age_Boville_Ernica[/TD]
[/TR]
[TR]
[TD="bgcolor: #5300FF, align: right"]27.54563123[/TD]
[TD]R851_Iron_Age_Ardea[/TD]
[/TR]
[TR]
[TD="bgcolor: #0000FF, align: right"]30.24831400[/TD]
[TD]R435_Iron_Age_Palestrina_Colombella[/TD]
[/TR]
[/TABLE]